The Caterpillar "Pony Motor" - Cursed by Design?? Or the Perfect Balance of "Just Enough"???

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/ @squatch253

[@JustaFewAcresFarm]

Hi Squatch, great discussion, and it got me to thinking about the Farmall M diesel I spent last winter doing the engine rebuild on. Its starting system was another option, which essentially incorporated a pony gasoline start system right into the main diesel engine. No one used this option except for IHC, and they developed it in the 1920's, as a way to achieve the efficiency of diesel power before glow plugs, batteries, and starters were strong enough to crank over high compression engines. Like pony motors, this system eventually disappeared with advances in technology. Before I went through the engine, I thought it was a poor system, as the tractor would hardly ever start below 40 degrees. After rebuilding it, it easily starts on gas in just about any temperature. During the process, I learned that one of the most important aspects to the longevity of the whole system is in how it is operated; the proper steps taken to start it, cool it down before shutdown, and the gas/compression settings to leave it in after it is shut down. This is similar to your discussion on pony motors getting a bad rap due to poor maintenance.

[@mathdj01]

My I ask, how many different shirts were worn during the writing of your response?

[@rinardman]

I grew up with a couple of Farmall MDs. The first thing I learned was the proper way to start them on gas, how long to let them run before switching to diesel, and then switching back to running on gas before shutting the engine down. As long as the gasoline side was working as it should, it was very reliable. You just needed to properly maintain the gasoline starting side of the operation.

[@DOCTORDROTT]

@@squatch253 Would love to see you upgrade one of the three engines to electronic ignition as it would improve reliability and starting made easier. They can be temprimental, the Wico mag on my D4 seems a lot more reliable on the Eisenmans I have on other Cats. What do you think ? Will be working on my Cat D2 3 j soon. its number 3j506

[@edwinhsingmaster9135]

As a retired auto mechanic I didn't realize until recently, talking to a motorcycle restoration friend that the magneto magnets needed re-energized in old distributors, resulting in weak spark. Probably the wrong terminology, but you get the idea. Does that apply to all magnetos?

[@dans_Learning_Curve]

Good to see Pete in the house!

[@bobpackard9527]

Great memories. Back in the day, I was driving a DW20 Cat Scraper for a contractor. Removing overburden on an opencast coal mine. Summer work, mostly, for rubber tyred machines, as the final layer was marine clay. Slippery when wet!! Shift length? 14 hours. Season length? 8 months. 6 day week. pony motors were run ONCE per day. After a start, we ALWAYS let the pony's run out of fuel. I never heard of one dying.

[@ironman3406]

Absolutely nothing wrong with a starting engine!! Chatted with an old Cat engineer once and there is good reason Cat stuck with a starting engine for so long even though electric was available from some of the competitors. Cat had some of the higher compression Diesel engines out there, and keep in mind they started building diesels in 1931, at that time there was no electric starting technology that was sufficient to crank over the high compression Cat engines. Thus the starting engine was born, Cat ran starting engines so long, in fact it wasn’t until they were confident that electric starting technology was reliable enough to get their engines started that they did away from starting engines. (Starter, glow plugs, battery, etc). Even though electric start began to become available you still had the option of a gas starting engine for some time before they disappeared. In climates up here in the winter you couldn’t rely on batteries to get the 2UD8 running in the morning to clear bush. But so long as you could crank up that starting engine, get the diesel spinning over (sometimes you had to burn a whole tank of fuel before you had enough heat for the diesel to pop off) but you could always get fired up to work for the day. My grandpa tells me stories of how he would have rather had a starting engine that was well maintained vs an electric start especially in the winter months as it was much more reliable. Btw if you want to run a D8 with a pan for a week just come on up man we’ll let you loose :)

[@dans_Learning_Curve]

Enjoy stories like these! Where are you located? How far north? I'm in MN.

[@ironman3406]

@@dans_Learning_Curve central Saskatchewan

[@fcp5039]

Well Caterpillar did so love their pre combustion chamber engines. The down side of them is that they are not really good at generating enough heat in the combustion chamber when you crank the engine over. That is why the need for the pony motor starter, or the later glow plugs to provide a source of heat to get the diesel fuel to light off. Direct injection diesel engines this isn't such a big deal.

[@peterscandlyn]

I was told some years ago that engineering recruits to Caterpillar, as part of their training were seconded to Briggs and Stratton to learn engine design. Many baulked at that considering B&S were so far below their level, despite at that time being the largest engine manufacturer in the world.

[@JAMESMANHUNT9]

@@peterscandlyn I worked on Briggs and Stratton 4 stroke singles in highschool I have a Briggs and Stratton genset that runs off ng

[@TomokosEnterprize]

I have had D2s with rope start all the way up to a 9G with electric start and even at -40 in time the dozers would start. When I lived in Norman Wells NWT Canada I worked for a pilot and road builder. He found 10, D2's up on the Canol line from WWII 2 men can lift any part of the still greased packed parts. We brought 6 of them back out in a Pilatus Porter. When assembled they just fired up like they were brand new. Thanks a bunch for going through this for us. Lots of good memories of when I was young and strong.

[@petebrand6661]

as an amatuer the pony motors maybe archaic by nature BUT when used to pre-heat the main engine quickly and effisently there is nothing archaic about them, and i applaud you Squatch for the amazing series and renovation on this little tractor

[@rustyreckman2892]

I like the starting engines. I like that they’re serviceable. Everything today you throw away and start over and that upsets me

[@wsbrand]

I like starting engines. In this day and age any machine that works without an electrical system is cool awesomeness.

[@PacificNorthwestHillbilly]

Using the fuel shutoff to stop small engines is still the best practice today, especially on equipment you only use every few months. Waiting a few extra moments for the engine to run out of fuel sure beats cleaning the gunk out the carb every year.

[@paschaldobbins8430]

I always unhooked the fuel line on my Mercury outboard backin the day. Never had a carb issue.

[@kylechrist]

I like the principle of the starting engine, saved wear and tear on the diesel trying to start for the first time of the day. With that being said, I did put a Cat factory electric starter on my D4 7U as that had the removable 3 bolt cover in the bellhousing. I figured another starting method is never a bad idea, but the early machines never had that option, like the RD-4 or 5J1113 (other than pull starting them) Great info as always, thanks Toby!

[@joehovanec1985]

It sure is nice listening to you talk about what you're working on. This country could use more people like you.

[@robertvogt5606]

An old operator told me when he started his career he was an oiler & showed up before sunrise & they always kept one pony motor on one doser in good working order & push started the rest of the equipment

[@humancattoy7767]

The design was exactly what was needed. The pony motor needed to be simple and able to take abuse.

[@jonathanstancil8544]

@@squatch253 that's another major point: how much did that 3400.cost to rebuild/replace when these machines were still relevant? How much down time? Did the owner or dealer have an easy way to get the machine on a truck and to the shop? The starting engine reduces a LOT of those issues to naught. And if the starting engine died out in the woods it could be removed and replaced relatively easy.

[@casparberends2719]

@@squatch253 only thing I wonder about, why so little oil in crankcase? This makes the ponies much more vulnerable than necessary.

[@danielstickney2400]

@@casparberends2719 I think you can answer that question with another question: Where would you put it? The oil capacity is constrained by the size of the block. More oil means a bigger engine for what benefit?

[@brianlittle3452]

Many of your viewers are looking at the pony starting engine with a 2021 perspective. A better way is to look at the pony engine in the period that it was designed and built. During this time, horses were not a distant memory. I thought it took a lot of time to start a D2 until I realized that getting a horse ready for work took a lot more time compared to the pony motor. Twice every day, in the morning and night, the horse had to get fed. The horse had to be watered multiple times in the day. Then there was cleaning out the barn… On a related side note - I remember you talking about one of the drain tubes on the main engine. The mess made from that drain tube was far smaller than the mess made from the horse.

[@mpccenturion]

I will not say we abused the Start Engine. Much North of you - I recall in -15F weather - I ran the Pup for 10 minutes - before we closed the Compression valve, It was 20 minutes before we got on the rig and hit it with fuel. If the engine did not light up - I left it another 15 or 20 - and once running, never shut it down for 8 hrs. Thank You!

[@robertquast9684]

With those older Diesel engines even a new modern gear reduction starter would struggle to survive with extended cranking times let alone battery life. I would imagine more than 1 old Delco starter was melted down trying to start them

[@joekahno]

Back when I was learning to fly one of the things my instructor hammered into me was that you shut down a light aircraft engine by leaning the mixture not the mag switch. The switch works by grounding the mag. If the wire breaks the mag stays hot. The mag has an impulse coupling. If it stops at the right spot, a slight nudge and a few gasoline fumes can give one more pop, enough to swing a prop blade. No big deal except one of the few places you can grab a light plane to move it on the ground is the prop, close to the hub.

[@davewalls752]

I have two magnetos for them ,they started in severely cold winters here in Alberta Canada so great for rotated main engine with long periods before start up 😊

[@larrybolhuis1049]

I never used a Cat pony start but ran a JD 2-Cyl Diesel for years with a Pony start. As you described the later Cat versions it did heat the intake manifold with its exhaust. It was also water cooled and heated the diesel block. It was a 4-cyl however and had two speeds, run and start. Run to warm the diesel and start to start the diesel. Most of the year we could start the diesel in 10 seconds if it was arm. If it was cold, perhaps 20 seconds including time to see oil pressure before releasing the decompression lever. If it was cold (below zero F) then we'd let it run for 10 or 15 minutes and the diesel would fire right up. It always worked and didn't care about cold. The biggest downside was the tractor thus had a 6V system so it was good you did field work at 3 or 4 MPH because if you were going any faster in the dark you wouldn't see the fence in time to stop! LOL!

[@dancaszatt7573]

Those engines are a beautiful setup. For the simplicity and functionality.

[@wildcoyote34]

i have heard a lot of guys complain about starting engines and i agree with you ,, I have a 1959 john deere 730D and it has the pony start and i love it ,, minus 15 degrees ,i can go out start the pony engine , let it run and warm up for about 15 minutes ,, that's time for a cup of coffee ...go out jump up on the seat ,pull the compression release , hold the clutch ,wind up the pony and i do mean wind up too cause it'll hit 5000 rpm ,engage the starter and it'll turn maybe 8 revolutions before it clunks to life ,,that old devil will start when my newer 4960 won't even think of waking up till i plug itin for an hour,,my grandfather bought it brand new and it's still on the farm 63 years later being used to plow snow

[@oldamericaniron5767]

I’m from the school of liking starting engines, especially when bleeding diesel fuel system. 45 years ago I ran a Bucyrus-Erie 22B with a D318, rope start only pony. Would generally start in 1 or 2 pulls. Yes, always, always shut off gas and let run dry and besides preventing oil dilution the carb will be dry so it won’t gum up if let stand for extended periods of time. The 22B I spoke of sat for about 15 years, I went to start it, poured fresh gas in tank and it fired up like it had been run yesterday.

[@mikes1345]

Didn't know anything about starting engines until I found your channel. The concept of no battery has a certain cool factor. Older technologies are way more interesting than these computer designed and operated motors today. Of course the skills of the restorer is just as interesting. Keep it up.

[@A50S2D]

In 1970 I worked on a ranch in South Central Idaho. We had an old D7, an even older 1HD8 and an IH TD6. The pony motor on the D8 cranked from the front of the engine and would either start on the first try or not at all. The D7 cranked from the top and if you weren't careful would kick back and throw you off the track you stood on. The D7 pony motor would start most of the time but not always willingly. The TD6 started on gas and then would be switched over to diesel. Some mornings I would eventually use the TD6 to push start the D7 and then use the D7 to push start the D8. Lots of fun the summer. I did use the D8 to pull a cable scraper with the D7 pushing the can for a few weeks building up pads for irrigation ditches. Lots of memories from that summer...

[@royalhudson4612]

My Dad owned a small town power plant in the early 50's. Ran 24-7 except for oil changes. He said the engine vibration caused more damage to Pony motor than actual use. I wish I could remember what part he was referring to.

[@danieldudzik6470]

I love the starting motors. It is the only way I ever learned to start the old cat road grader we had at the field. Before I was around, my buddy had the road grader with a pony motor, but the carb was junk. He used to park it at the top of the property and roll it down the hill shooting it with starting fluid. One day he took a miss step and almost fell between the wheels, that was too close to death or worse for him. He spent the next day milling up an adapter for a jet ski carb to be attached to the starting motor and used the starting motor the rest of the time he had the grader at the field. He was good at adapting and over coming. Fond memories.

[@NineCylinderDiesel]

I've always been a fan of the whole concept of starting engines for the exact same reasons you mentioned, particularly for large diesels.

[@arkwoo]

We had a family logging business in Northern California while I was growing up and I spent a lot of time out in the woods with my dad and my brother. The very first Cat I ever saw (and operated) was my Dad's old (even then) 2U D8, cable blade and all. It was outfitted with a canopy, logging winch (no arch) and a simple straight blade, nothing exotic. This was back in the 60's and I was probably 10 or 11 years old the first time Dad let me operate the D8. I remember those old snap-over-center frictions - I was just barely big enough to pull them back and reach the brakes to turn the Cat. I pulled a lot of bull line and set a lot of chokers behind that old Cat and I saw my Dad take that thing places I would never have dreamed of - diving off the top of a ridge yarding logs, or cutting new logging roads in steep mountain country. With hydraulics and automation today most operators have a lot of advantages those old school cat skinners never had. I can still hear the 'pop-pop-pop-p0P-POP-POP-POP-zzzzzzZZZZZ-rumble-rumble-RUMBLE-POP-Pop-pop...' of that old diesel starting with the pony motor and then the pony motor fading away. That always signaled the start of the work day for me back then. And then in the evening when you finally shut that diesel off, how still and dead quiet things were in the woods, after listening to the Cat work all day. Under heavy loads you could hear individual combustion events when the diesel would lug way down, pushing dirt, rooting stumps or pulling a heavy turn of sugar pine to the landing. Wow, that was sure a long time ago :) By the way, Squatch, I very much enjoy your channel. Given my upbringing, I worked for a lot of years as a diesel mechanic and millwright before walking away from that to a new career in IT (of all places :). Watching you rebuild this gear is like an echo to a much earlier part of may life :) Keep up the good work !

[@normsweet1710]

I was all set to find one and rebuild it…… then I heard 30-40 yrs outta production overhaul kits………well shucks . Just like anything else you operate that’s been quality engineered : YA GOTTA KNOW WHAT YOU’RE DOING TO RUN IT AND DO IT RIGHT. you keep building and I’ll keep watching 👍❤️😉

[@elricm13]

Great video! I have run equipment with starting engines for 45 years. If you take care of them, they run and operate perfectly. Where there are complaints, the issues could be traced to poor maintenance, no warm up, no cool down or low oil. The starting sequence is important to take care of the pony and Diesel engine. Love my pony start equipment! The main reason starting engines were used is the lack of power in the 6 volt starters, the wouldn’t turn a diesel over under compression, whala the starting engine was born. Thank you again for all of your efforts!

[@sunelarsen]

Fun Fact those plug style pistons. Thats the same system used in morden Top Fuel (12000hp) and Top Alcohol (3500ish hp) race engines.

[@scottthomas5999]

You are absolutely correct on the starting engines.

[@sailinwrench]

I originally found this channel because of my interest in learning more about "pony" motor starting systems. That alone cemented my opinion of these little gems lol!

[@yokiniqu]

The starting engine is part of the character/charm of the tractor. As a kid, watching my Dad 'start the D2', the unique crackle of its exhaust note, the diesel engine starting with associated plume of smoke when the throttle was cracked open, this was all mesmerizing to watch. Unfortunately I don't have my Dad's D2, but I have one just like it. The starting engine is a winner in my book.

[@npalen]

Dad's Rd6 was started weekly at midnight on Sunday evening and never shut off until midnight the following Saturday. It was pulling a seven bottom moldboard plow 24 hours a day turning wheat stubble in NC Kansas starting in 1936. The tractor was finally retired and sold in 1965.

[@markmoore4088]

Wow!

[@felixchetlanddevries2998]

I was digging through the scrap pile at work and found a tiny crankshaft and 2 pistons on rods. Just from you videos I was able to identify them as off a d2 starting engine. They were completely toast after being buried is the dirt for approximately 50 years.

[@Shadow0fd3ath24]

i was thinking 2 large off the shelf semi truck starter motors and an ignition switch would have worked just as well and been so much easier and cheaper, BUT after thinking about it more... these pony motors worked well for a long time and didnt need a battery to turn over and get the dozer moving even if the main big engine didnt run at all. Their magneto system and hand cranking reminds me of the Ford Model T (and they also only had splash lube and small amount of oil capacity)

[@stuartmcewan9620]

I agree with you. Back in 38 who had a starter motor to turn the diesel engine over to start. Nope.! . Only a pony motor could start the engine. Lucky I have two pony motors just in case one lets me down. Enjoying your insights. Thank you for your show.

[@Matt2chee]

The switcher at the Collinwood Yards ran 24/7 They never shut it off unless it needed work. It was nice to have a warm cab in the yard when it was cold. In the "old days",CAT would have come in R&R the unit, put on an overhauled unit and return the core for service. I was in the new CAT facility in Ohio. The service and repair department is amazing. They have a huge dyno. and hoists that can pick a fire truck no problem.

[@elricm13]

A retired excavator lived next to me, lots of alignment been your comments and his! He also said they used to lubricate the tracks in the morning with diesel fuel, pouring it all over the tracks…..yikes! Great videos, thank you!!

[@vburke1]

The threaded dowel pin modification is a GREAT idea, but you know the bean counters were watching even fractions of pennies.

[@bevanwilson5642]

I have talked to a few of the old guys in the thornbury vintage club in southland New Zealandthat I am a member of and they have said that 30 to 40 thousand hours was not uncommon between O haul of the main engine in the D2 and D4 crawlers and that was probably hard work as well

[@cassiuspuckett8789]

I'll be honest with you about starting engines. I've never experienced starting engines except to watch them being used from a distance. But I have experienced electric starter and air powered starter. And from your explanation of the starting engines, it's definitely worth looking into the rebuild of the starting engines. The benefits out weigh the convenience of the other ideas for starting the diesel engine. Thanks for sharing your thoughts on the starting engines....

[@eaglewi]

I have to admit the air start is reliable too,

[@LionWithTheLamb]

My Grandfather used to say that he liked the pony motors better than electric start. He did a lot of logging back in the day. He liked magneto's, points, and updraft carburetors.

[@ogr7771]

I love the pony start, in the late 70's as a teenager I worked summers at a Boy Scout summer camp and we had a late 40's D-4 and I used it every week, just loved the routine of starting it, though ours you started from the driver's seat, had a diesel engine pinion engage knob on the left side of the dash and the compression leaver and pony throttle and choke were on the right side, have never seen another like it before or since.

[@ron827]

Treating a starting engine like a diesel could make them last longer. Let them idle for a period of time to warm them before applying a load. Also let them idle to cool down before stopping.

[@georgeholmes96]

Their is nothing wrong with the pony starting system John Deere used it on their first two cylinders tractors just take care of the ponys and the horses will do the work

[@michaelwebb4833]

As always love your personal opinion on the technical side of everything that you do. Till next time thanks

[@tangydiesel1886]

At least they put a real carburetor on them. The deere model R's got a "mixing pot." Basically a manual adjust fuel needle and the leather flap. It's simple, but you had to adjust it for the temperature. Might be 3/4 or less of a turn for a hot start in the summer, or 1 3/4 for a cold winter day. At least the tank is lower than it so it doesn't leak into the crankcase, but if you flood them, you really need to change the oil. Later ones, you could change the fuel valve from the seat and shut them off that way, but early ones, you only had a governor control.

[@hoeguy7862]

First Dozer I ever ran was a 69 D8 with a pup, little temperamental but always started up the main. Second was a D7 same setup, got the job done too.

[@garyvukich5790]

I worked for Ziegler in Hibbing (did mags /fuel/starting motors. 1959/60

[@rdecoster1]

I don't know much about diesel engines or Cat bulldozers. I subscribed and love to watch you put stuff together with care and precision always double checking everything. Plus you have a cool shop and everything is nice and clean and organized.

[@frankmchutchison9436]

I have a 1956 d4 6u and the starting engine has never failed in the 35 years I have owned it and as said Never turn the ignition switch off ,always Turn the fuel of and let it run dry, no issues of fuel in the crankcase, and yes it is a great way to get the main engine warmed up. Thanks for sharing

[@clydeschwartz2167]

Excellent video the starting engine definitely has it's place especially in a cold climate like Minnesota and a lot of areas electric start system would not have enough battery capacity especially in the time era when 5j1113 was built it takes a good starter to get a modern diesel engine running. The short block is looking good. When I was growing up we had a John Deere 720 diesel tractor with pony start the engine was not in great condition but it always started the big 2 cylinder diesel engine. Then years later I got a 720 John Deere diesel tractor with electric start and it would start to 40 degrees and any thing colder forget it I wished it would have had a pony motor I did not keep that tractor very long because of the poor starting with electric start. That's my experience and even a modern diesel a gear reduction starter makes a world of difference for starting in the cold weather

[@sparky167]

Correction 5j1113

[@martinkennard1669]

I was running a D-2 Cat when I was 10 years old. The starting engine was a thrill to rope start and operate the clutch and engine. It always popped right off.

[@fredf3391]

Your spot-on about starting engines construction n longevity .In 74 JD 2cly mechanic ( nowadays technician) said farmer's just wanted to push starter button and go not Tinker around with starter engine .Back then you just ran it n traded it in for something new, ,it's a circleback moment because now the emphasis is on restoring them back to New .

[@keithross4511]

I’m pretty much like you. On my old Cat D6 4R series crawler, l always enjoyed firing up my pony motor. It’s rope pull start. Made sure I had a good mag to throw the fire at it. Made sure the carburetor was clean and adjusted well, and oil was clean and full. Is mounted and plumbed in a little oil gauge to the top of the starting motor so I could squat down there on the tracks as I’d be cranking and turning the Diesel engine over getting it warmed up, and could monitor my oil pressure, making sure my diesel had good oil pressure. Plus it was warming that diesel up. And something about just listening to that pony motor purring away and turning that diesel over until I was satisfied she was ready make some smoke. Crack my diesel throttle open and reach down and place that compression release leve to “run” and that diesel would fire up every time. Man that moved me around with his semi lowboy told me, one thing he always could rely on, was when he came to move me, he knew my Cat was going to start, and we’d get loaded and be on the road in short order. You take care of that pony motor, and it’ll take care of you. I also never used that kill switch. Is always turn that wing nut cock shut-off on my sight jar close and let the pony motor run itself out of gas to shut down.

[@willmarshall3552]

I Have a 49 Model R John Deere with the 2 cyl starting motor. At one time cat and jd were married at the hip, thus jd having a starting pony motor. Great stuff. Always starts, warms the main engine, it takes some time to do that when it is really cold, but always starts. Thanks for the presentation.

[@Pete-ln4vu]

TOBY!! YOU ARE RIGHT ON THE MONEY ABOUT STARTING MOTOR'S!!! I'D RATHER HAVE A STARTING MOTOR THEN ELEC START!!

[@dans_Learning_Curve]

@@squatch253 I see some people know your first name. Why don't you use it in your videos? Great video BTW.

[@austincjett]

I agree with only putting in enough gas in the tank to get get the pony started. Any more than that is likely to windup in its crankcase.

[@mikeyarbrough3065]

I know very little about the antique tractor subject and watch because you supply a straight forward honest opinion on what you are doing weather it’s the rebuild or field and the opinion is not jaded by anyone. I wish more folks had that way of thinking and thanks for the information, technical instructions, humor (sort of) and overall entertainment. Mike Y STL

[@kevinknight470]

Love those starting engines, especially for cold weather. Did not have an issue with diesel compression, all the machines that I ran had compression release controls.

[@dougcooper6004]

My Dad bought a new D4 in 1953 so I grew up around the pony motor. I still have the dozer. Have started it at 20 below zero by pulling one spark plug, giving it a little squirter of gas, then pulling the starter rope. Anything that can last 69 years on a ranch is impressive.

[@ronaldziehlke9720]

There's a constant in the law of manufacturing. You can make something good, fast, or cheap. You can only choose two.

[@mudfly12]

We had a D2 on the farm for awhile. Never knew much about the starting motors and I don’t believe we EVER shut the gas off to the starting motor. Of course we purchased the D2 from a jockey to do a job, it did the job and then eventually got sold. Never once saw and operators manual. The starting motor was not in great shape and definitely needed a rebuild. Makes sense as to why.

[@dans_Learning_Curve]

@@squatch253 cool to hear how you learned! Need more stories! Please!

[@generalpatton5080]

I agree squash, been operating these things for over 50 years. Being a heavy equipment mechanic and operator the best thing I like about starting engines is the important fact that the main engine has oil pressure and circulation before it fires. When I replaced my older cats with direct start I could just see galded parts. The old engines seemed to last forever however the modern engines just don't get the hours before rebuild like the pony start ones.

[@keithammleter3824]

I bought an old 6U D4 to do firebreaks on my hobby farm. The starting engine has always worked on a very old well used D4, so there is no criticism justified on its design. But I did discover not long after I bought it that the starting engine water passages were just about completely blocked with white muck. The benefit of a gasoline starting engine, with coolant common to the main engine, and starting engine exhaust routed through the main engine intake manifold, is that you can ALWAYS start the main engine, no matter how cold it is, nor how long it has been sitting since last start. So long you have a cup of gasoline and can pull the rope, you are good to go.

[@frankjackson2439]

I never understood why they didn’t use air starters. It’s not hard to make an electric auxiliary electric air pump to pump up the air tank when there low to start the engine. They could have even used a little pony motor connected to an air pump to fill up the air tank. Even an electric starter from this era has enough power to turn a small air compressor to fill up an air tank for an air starter.

[@donaldconnolly220]

When I was new to the heavy equipment..... And I mean green..... I was working on an old boat 78.... Foot Florida shrimper....... When the engine blew out of it... The owner captain.... Saw an old bulldozer out the middle of a field...... He bought the dozer and tore the engine out.... That was a cat d9.... It had a pony engine..... We hooked it to a Philadelphia Marine transmission.. It always started.... But being truthful about it... I didn't know what the hell that pony motor did I just knew that I had to hit that first and let it run for 10 minutes before we could start the d9....... I'm waiting for your d9 video

[@craigthoricht2214]

Another thought regarding these engines and old gasoline engines in general. So many people have trouble with their carburetors getting gummed up. I think it’s a relatively simple step to shut off the gas and let the engine burn through what’s in the carb. If there isn’t any fuel in the carb to make a mess, you have helped yourself avoid frustration and untimely repairs. I do this with my Farmall “M” and so far so good. Simple solutions can be good.

[@erik_dk842]

I remember my dad buying a Briggs and Stratton workshop manual, reading it and then religiously following its advice of always letting the carb run dry.

[@halsnyder296]

Having seen the video, I concur with your analysis. I really like the whole starting engine concept. I once had to start my old diesel Rabbit (foolishly went rock hounding to an old mine in the Colorado Rockies during the winter…) with a battery that had frozen and split. Used a 9v transistor radio battery to keep the fuel solenoid open, pointed it down the mountain, and let it roll in gear. After enough fuel (which had gelled) got pushed through the injector pump and back to the tank, it started to fire. About half a mile of black smoke and it cleared up. Drove it 200 miles + back to Denver without stopping. Great car, wish it had had a starting motor!

[@dans_Learning_Curve]

Great use of your resources! I wonder how many people would have thought too use that 9V to open the fuel solenoid?!

[@halsnyder296]

@@dans_Learning_Curve my job at the time was a small diesel mechanic, so I new the engine well. Mercedes used a vacuum solenoid, I would have had more trouble with that!

[@mfree80286]

@@halsnyder296 Would have sucked. (hah!).

[@sprint6855]

Personally, having a starting engine is what says vintage Cat to me. My great uncle ran a Cat from the 50's for the company he and his brothers owned until he retired in the 90's. Same machine forever, and it likely wasn't new when it was purchased. Adding pressure lube would have been great, but probably would have doubled or tripled the cost. Adding a pump and oil capacity seems easy on the surface, but pressure lube would have necessitated block casting changes, way more machine work drilling oil galleries, and a solid crank would have been needed. All of this would have also increased weight greatly. Having no hands on experience with these, the only short coming I can see is they needed an updraft carburetor to minimize oil dilution when the gas isn't turned off.

[@RustyWheelRanch]

Hi, hope this comment reaches you, love what you do and what you are about, watching these videos have thought me a lot about old equipment, i have an opportunity to purchase a 1947 D2 with scraper blade for a good price, same story as always "RAN WHEN PARK'' my concern is getting it to start. over all it looks like a solid unit but I never had anything with a pony motor. this video made it very easy to understand the concept of them. THANK YOU!

[@two-strokesmoke7289]

Starting engines are the reason a lot of these"older" Cats still exist. (my opinion) Much more service life out of the main engine, most of an engine's wear is on startup (I have heard upwards of 95%)

[@dans_Learning_Curve]

Yep, the worst thing you can do to an engine is start it!

[@larrybl]

Really enjoy your series, especially the pony motors. I restore vintage Garden Tractors and I have several 18 hp Briggs opposed twin flat heads 70's - 80's vintage, that while more advanced (sleeved aluminum blocks, electric start, etc) they do share the more simple flat tappet designs, no oil pumps, and simple carbs, and I really enjoy working on these. Like you, I find this very therapeutic.

[@OldtimeIronman]

Your typical Briggs mower engine used similar technology for decades and look how hard those get worked. My old Wisconsin and Continental engines are similar (air compressor and welder engines)

[@jimzwies7729]

extremely interesting rebuild My father had a RD4 cat no blade from new in lower New Zealand from 1930s as a contractor pulling a moleplough summer and winter for 16 thousand hours.Had to replace the flywheel and bearing on starter motor nothing else. Main engine required three sets of main and bigend bearing shells in the first 900 hours untill a lack of a oil cooler was found to be the cause for the failure.Both the cat RD/D2 and the RD/D4s used the same sterter engine .

[@edstallard4931]

I had a 1950 D47U with a pony motor. At first, I thought about converting it to electric start. But the more I used it the more I began to appreciate it for all of the reasons you mentioned. It started every time and I didn't have to worry about a dead battery. I appreciated your explanation of the pros and cons. Thanks.

[@michellehoefer5922]

Thank you for the video.I appreciate that you aren't dismissive of the folks that neglected the starter motors maintanence. Lord Muck,on his channel, talked about a pony motor on a Belarus tractor. It was a two stroke motor because, he said, the lack of crankcase oil made it easier to start in the colder temperatures.Neat!

[@raincoast9010]

A great presentation and nice to see another pony being reassembled.

[@thinman8621]

My Dad was a heavy equipment operator in Iowa. I can remember him going to work early on really cold mornings. Start the pony motor and just let turn the diesel over for a while to warm it up just like you talked about in this video. Weak batteries, corroded cables, gelled fuel and worn engines with low compression made a lot of battery start stuff a no start. Of course, Dad did ever also use some ether he got from the neighborhood pharmacist. Stuff was really volatile. I can remember Dad saying you had to be careful with the stuff or it would lift a cylinder head. I don't remember and Dad's gone but knowing him he probably used the ether on the pony motor to get it started in the extreme cold.

[@larrywalker7759]

@@squatch253 When I was in automotive tech school in 1971, several of our instructors told us that they preferred to hold a gasoline soaked shop rag near the air intake instead of using ether to help a cold soaked diesel engine fire up.

[@thomasjefferson4492]

WHEN I WAS A KID IN THE 1950's,MY soul job was get up before the operators,and start the Engines on all the machines,then they be warned up and read to go ..I've cranked up pony engines a lot,AND I LOVE THEM,its the only way to fly out in no where..electric starts were a nightmare,to many dead batterys...

[@vincentdunne7197]

Electric start would wear out faster than petrol on long cranks. I don't know much about cat machines but have replaced more Electric starter motors in 30 years than I care to remember. Been watching this build from the start, hi from Australia 🇦🇺

[@stxrynn]

Thanks for putting the good info out. It is very hard for folks raised on the tight tolerances we work to now, to look at how things were done in the old days. I've seen stuff done by farm workers that worked, but were sketchy to the max. But times are changing... and not for the better. You are really helping guys see that. And it's important, especially in this day and age of less parts and longer wait times. Learning to make things last as long as possible will be extremely important going forward.

[@christophersilva4021]

We started the d2 at our work yard and left it running on the trailer to the job and not turn it off till it was parked back at the yard if it was a one day job. I bought that d2 from my boss and neither of us has had a problem with the pony motor

[@phillipmcguire7677]

In the early seventies I ran a 1967 D7E with a pony engine. Kept it so it would start easy ( tune up and maint ) When it got cold I could start that dozer when the newer ones would not start. Kinda liked the pony motor.

[@michaelambrogio5578]

Your correct about the starting engine. And people that operate them and know to is loss in the pass. That's why I find that the information you give is a piece of history. And information is key. Ty for what you share with us.

[@seastacker8582]

I think it’s cool how simple it is. Can’t think of a better way to piss Gretta off than starting a big engine with another small engine. 😎😂

[@seastacker8582]

@@squatch253 I’ve been cracking up all the “how dare you” stickers showing up all over old equipment and such. Can’t wait to hear this one fire up.

[@Shumab02]

Another benefit to starting engines that you demonstrated in an earlier video, is the fact you can still move the machine around with it if something goes wrong with the main engine. Big advantage when you need to limp it onto a trailer or into the shop.

[@michelbrodeur6055]

So true no more to be said.

[@Tommy65i]

First time commenting here ! I have to say I love watching your videos! I’m a younger heavy equipment technician up in northeast pa. It’s awesome to see the passion and knowledge you have for these old cats. Makes me wish equipment was still that simple.

[@greenmirror5555]

Personally a block heater using the nobles electricity, or stored in a heating building with new set of fully charged batteries and Kettering starter is the way to go....not sure why all these peasants are showing their bow string finger at me? More taxations and kings x woot woot! I learned a bunch after researching the pine tree riots! Knowing you can pull start that pony and heat all the main works on free ground at any time deserves a standing ovation. Honest trade among friendship! Article 1 Section 10

[@fbh31118]

I certainly agree with your analysis of the pony motor. I have a similar reaction every time I see someone put on a 12 volt 'conversation' on a tractor.

[@merrymanrc]

Someone was thinking it was good idea at that time but so many years later things change

[@darrelhowell112]

We have overhauled my D2 pony motor a couple months ago and since I have owned it for 40 years and use it quiet often, we were surprised how little internal wear it had. It a little low on compression so we thought it was time for a tear down. the valves had great margin left but leaking somewhat as were the rings. We honed the cylinders enough for new rings and that took 95% of the scratches out. Ground the valves and seats, the stems and guides were serviceable also. We did have to make a new main , it hadn't spun, but had .011 wear. Polished the crank and used the good rod bearings. I have changed the oil faithfully, turned the gas off after starting the diesel also. I also think the pony is very useful for heating the jacket water, preheating the intake manifold and prelubing the diesel before starting. We agree that the pony is very basic. Thanks for backing me on the use of the pony. Howell Machine, LLC

[@deanehill9730]

I am with you on the starting engine, such a novelty and a great way to warm up the main diesel. Thanks for the video.

[@andrewbrenneman9592]

My dad's d2 was I think a 4u or 5u model. It had an electric start for the pony motor. I remember that due to the battery being under the seat. And the diesel tank behind the operator seat. Which is my favorite model of D2.

[@jefflewis6331]

In the late 1950's I-81 was built through northeastern PA. I lived two doors down from where they parked the cable pan scrapers and pushers at night, so we didn't need alarm clocks that summer - just after daylight every working day we were up just after daylight when they started those monsters up. Pony motors first, then the diesels. Everything was D-8's as memory serves. Anyway, the point is that yes, the pony would run for maybe five minutes, then the diesel would start, and it usually ran 10 hours a day or more. So your question about how good does it need to be is right on the mark.

[@michaelbaumgardner2530]

You covered all the questions on my mind,excellent episode.

[@rohanburgess3320]

About not shutting down machines. I remember reading a book about the construction of some of the Australian outback roads like the gunbarrel highway. Apparently they broke the starter on one of their cats and just ran it for a week or more while parts arrived

[@kenbellamy6085]

Hello, Squatch, on the subject of how good or bad the old starting engines were, my opinion is on Caterpillar or John Deere, they were as good as they were taken care of. So many of them were neglected and ignored, they were terrible, taken care of, they worked great.

[@smitty1952]

Squatch, it would be great, (but yes a lot of work for YOU!) to see a complete video inventory of all your vehicles. Completed ones, ones in progress and even ones awaiting a future tear down. From what I can see, you have a lot but I think everyone would enjoy seeing ALL of your tractors and Cats.

[@imdeplorable2241]

Your explanation made perfect sense to me. Thanks.👍