Erratic Lawn Mower Engine Performance - Starts and Runs Great / Stalls or Will Not Start

I picked up this Toro Recycler lawn mower a year ago for free and and made a video on it (video link below). Shortly after fixing it, I gave it to a friend. He ran it for 10 minutes and stalled. He was able to restart it after letting it sit. Every time he restarted the engine, it would for less and less time before stalling again. So what did I overlook the first time I fixed the lawn mower?
Original drive system repair video a year before: • Free Smoking Lawn Mowe...
Engine Model: 128T02-3125-B1 Code: 10031159
Lawn Mower Model: 20332
Fuel Cap Part# 692046: amzn.to/3BzX06Y
I use Harbor Freight Super Heavy Duty Degreaser in my ultrasonic cleaner.
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#SmallEngineRepair #SmallEngine #DIY #Fixed #Troubleshooting #HowTo #LawnMowerRepair #MowerRepair

[@watermanone7567]

Hard to believe that the fuel was so dirty in the bowl. I recently installed a new carb on a WX-10 Honda water pump and it ran great. Three days later the guy said it won't start. New carb was full of Rusty gas and water. I replaced it again and took it to his house and saw the old rusty gas can he was using. The fuel must have been 3 yrs. old and the inside of tha can was all rust. He swore he used new gas, and then blamed his kids for using old gas. I told him not to bring it to me again. Thanks for the video.

[@JohnSmith-yv6eq]

@@gags730 Small in-line fuel filter between the gas tank and the carb on every mower would sort this rust problem out....

[@thomasmagiera3283]

Yes. Non mechanical people are the worst enemies to their own equipment.

[@chuckmayerchak3071]

I give you a ton of credit for your thoroughness and perseverance! Most people would never have found that problem.

[@kajem575]

Thoroughness* 🙂✌️❤

[@chuckmayerchak3071]

@@kajem575 I'm not much for spelling. New phone and spell check must have left me down!

[@kajem575]

@@chuckmayerchak3071 Ahh we all do it. Hey,you got perseverance right. My prob. is usually small keyboard as to size of fingers causing typos. 🙂✌️❤

[@gradyhernandez4699]

True!

[@genesmay6589]

First thing I check when an items given or brought to me is the cap. Learned that the hard way years ago.

[@alsouthern7190]

I thought it was a fuel problem but the gas cap was a new one to me also, great job!

[@philliphall5198]

We replaced around 75 % on riding mower that are 5/10 years old They rot on inside of the cap and most mechanic think it’s fuel hose Rubber really rotten in tinny peace’s

[@blahblahblahblah2933]

That was almost super unsatisfying until you found the gas cap issue. Always nice to find something you can definitively point to as the issue. Nice work.

[@donho1776]

It would be interesting to determine how the original cap was supposed to vent and why it failed.

[@tarstarkusz]

I think he should try to rebuild it. That way he can figure out how it is supposed to work. It would make a good video, IMHO.

[@esqueue]

My guess that I posted is that it vents from those rectangle holes at the bottom of the cap. The long and narrow paths eventually got clogged up. Ultrasonic will most likely clear it up.

[@MM-wt8oc]

I don't think it is ment to vent unless the pressure is high enough. (think pressure cooker or hot water tank) The cap is ment to keep the Ethanol under pressure to prevent it from evaporating. Just like the new gas cans.

[@tarstarkusz]

@@MM-wt8oc How would it do that? Where is the pressure coming from? Are you saying when it runs the pressure will rise and then the cap will retain the pressure while it is in the garage over the winter? The problem with such a design (assuming it's possible) is that if the tank holds pressure above 1atmosphere (only possible if it seals), then as the fuel drains while you are running it, air cannot get into the tank and if the pressure in the tank is lower than the pressure in the bowl, it won't flow. It's like when you dunk a straw in a soda and then cover the end of the straw and lift it out and the straw doesn't drain.

[@chrismcgowan3520]

@@tarstarkusz he is saying when the pressure drops as the tank tries to provide fuel to the carburator and the cap does not vent creating a low presure in the tank, he also explained that it can cause issues if the tank gets warmer from winter to summer causing the tank to swell under extra pressure ((2 seperate issues from the same problem lol) this video actually solved an issue I was having with a generator (I didn't even think the small air his when I opened the cap was an issue, I was wrong lol)

[@P_RO_]

Inside the bad cap is probably a valve, similar to the disk valve in a vehicle's radiator cap. That lets it build pressure to a certain level before releasing, but also allows a vacuum to open the valve. Gummy-goo ethanol gas glued the valve or it's holes shut, thus you had excessive pressure and no vacuum admittance. Let's have a cap deconstruction to see what's going on with the bugger 😉

[@philliphall5198]

The rubber gasket in cap rots and stopped up fuel supply It’s really common so check inside cap for damage and replace it every 4/5 years for sure

[@johncourtneidge]

I agree that sawing the cap in half, or less drastic action would be worthwhile.

[@Ram14250]

Good video! Who would of ever thought a fuel cap?

[@robertgad3269]

Here is why I really liked this one. Many years ago (many, many), I had a British sports car. It had suffered minor body damage from a parallel parker, near the fuel filler. Picked it up from the body shop, and it died on me on the way home. I was mystified: the car had always run flawlessly, and the body repairs had nothing to do with anything under the hood. (Er, “bonnet.”) Before getting out tools (something one always carried with British cars) and fiddling with the carbs, I decided to smell the fuel in the tank. Spun off the cap and heard the air rushing in. Left the cap off, drove to an auto parts store, bought a vented cap, and drove home no issue. Apparently the body shop had replaced the filler cap and, back then, one had to be sensitive to whether a given vehicle required a vented or unvented cap. All that said, I got all the way through this video and never thought about the cap. Oh, well.

[@alext8828]

Good story.

[@cbauer72]

I had a Toro mower that did almost the exact same thing. I called it my "Union Mower". It always died about 30 minutes into a mow and wouldn't work again until it had a 30 minute break. I came to the same conclusion as you, it wasn't venting properly.

[@russbenner4872]

Replaced cap on mine and it was not the issue , the issue was the gas had clogged the output of the gas tank took it off and cleaned with hot soapy water let it dry and reinstalled added gas and works perfect ".Ethanol" clogging fuel systems since 2005 just add the fuel preservative oil that keeps the corn from absorbing water .

[@daniellang6112]

Ethanol free

[@iantyler4045]

Nice find. That's probably the last thing you would suspect but it just goes to show it's often the simplest thing causing the problem.

[@ni_wink84]

Once again James’s attention to detail found and issue I wouldn’t have even thought of, and once pointed out made perfect sense! Great video I now have another item to search for when working on small engines

[@davidfoulk3078]

What you do is amazing. When I was a kid in school that was gonna be my career yeah, fix small engines, but my high school shop teacher told me don’t do it cuz there’s very little money in it.

[@c.hundley9714]

I remember the metal caps with a vent hole. I miss those days. I still use my 1965 Briggs. I've replaced the rings once in 1988 or so. Did the valves too, since the head was off. Outside of replacing the rope a few times, never a problem. It was my grandparents mower. I keep the oil changed and run it empty every fall. It'll get passed on. Bad cap....that took some thinking cap. Great work.

[@markyoung7470]

Another fantastic video from the small engine master thank you James your tenacity is incredible!

[@jackmahogovv]

I love the the thought process you use troubleshooting these kind of things. I probably would have just drilled a small hole in the old cap instead of buying one, but Im cheap like that.

[@tubeDude48]

I would have never guessed the CAP! Nice job Jim.

[@bilseaman6168]

James, our lawn mower would not stay running. Replaced fuel, air filter, spark plug, and blade. As soon as the prime burned, the engine quit. Watched your video. Went outside, loosened the cap…magic! It ran great! You are a genius my friend. Gravity feed systems need that head pressure in the tank or the engine will starve. Thank you. Next stop, new gas cap. Cheers!

[@jcondon1]

That can be a hard one to diagnose. Easy fix though.

[@r8118830]

Thank you for this one James. You certainly come up against some rare faults. I have seen you check gas tank fuel caps before if you suspect a possible airlock in the fuel system. This is the first time that I have seen you find one though. I must be cheaper than you because I would just have drilled a very small hole in the cap to allow the passage of air. A size 80 gauge drill bit with a diameter of 13.5 thou would be fine. It would have saved five dollars. Thats just me. I am sure that your approach is more professional.

[@mtcman42]

A while back, I was given the exact same lawnmower with the exact same problem, and like James, I went through the same procedures until I found the problem. looking into the tank, I saw a very small white plastic tube in the intake and not knowing that it was some sort of filter, I pulled it out. Didn't fix the problem, but it ran with the cap off. Put the cap back on and engine quit a couple of minutes later. I pulled the fuel line off at the tank and no flow. Opened the cap to look in and gas started flowing. Put the cap on and it stopped. Upon examining the cap, I found no air vent hole, so I peeled back the little rubber gasket inside and drilled a .030 dia. hole thru the top of the cap and it ran fine. The other owner had taken it to two different shops, and they couldn't fix it. New air filter and blade sharpening and sold it for $120.00. Next time, I'll start with the cap. I would be worried about the "dished" cap letting water in. Where is the vent hole? Mine was domed.

[@r8118830]

@@mtcman42 Well it worked. You are right in worrying about the shape of the cap possibly letting water in. Choosing where to drill the hole then needs care. At the conclusion of James' video, his solution was to buy another cap with the vent hole designed into it. The designers of that cap obviously had the same problem to consider and must have acted on their view of it. It would be good to see the exact design of James' new cap as you say.

[@r8118830]

I decided to revisit the video. At 24 minutes in we can see the new cap as James looks at it. From there to 25 minutes James points to the hole in the cap. The top of that cap is definitely concave. That would certainly hold water. The hole is not at the bottom but some way up toward the rim. Perhaps to reduce the risk of water ingress. The diameter of the hole would influence the possible inflow of water. The bigger the hole the bigger the risk. I wonder what the size of the hole is in James new cap.

[@jimw6991]

​@@r8118830Water needs a larger hole than air. Drain holes for water are usually 5 mm. Air vents can be smaller. That said why not have a dome on cap? Many systems vent fuel tanks with a hose to the carb area, another proven design.

[@rancelynch6514]

Rance here Jim. What an astute observation ! But that’s what I have learned to expect, another very enjoyable and instructional video.

[@nicksnarski5973]

I would never think to look for that.Nice catch.I really like those older flat head Briggs engines. Quantum and Classic.

[@butler386]

What a pain but a very good lesson to remember. Always check the simple things first which is sometimes hard to remember to do. Great diagnosis for sure. Thanks for the videos.

[@stevefrayne7253]

Similar to an issue I had w my 40+ yr old Stihl chainsaw. Had me perplexed for a while.It came up when I serviced the saw and replaced the fuel and vent lines. To vent Stihl placed about a 1/8” set screw in the end of the vent tube. Thinking must’ve been that air could work its way past the threads but sawdust wouldn’t. Saw would start easily, run great for a minute or two but would starve and die. Finally figured out the new fuel line I’d installed was much more supple than the old and the set screw moulded to the line so no venting. Found small air filter like ends on the internet that push into the end of the vent line and ‘voila’ runs great. Never miss any of your vid’s.

[@jcondon1]

Thanks Steve

[@mrobi5797]

Good leaning curve. We rarely asses a simple thing as a gas cap to be a problem, it is also an issue on cars once in a while. Thanks James.

[@mjg263]

Great diagnosis and easy to overlook. I had this same issue with a couple of older Honda HR214 mowers. Honda used a foam filter material inside their gas cap vent passage to keep dirt out (they still do). Unfortunately the old foam broke down and solidified over time blocking the vent and causing the engine to starve after about 10 minutes or so. I replaced the foam and they both ran great after that. Briggs also went through a few gas cap design changes in an attempt to “improve” things and they ended up with the horrible design they have now. It’s a half-turn cap that won’t stay tight, leaks fuel all over and traps grass clippings and dirt under the edge that fall into the tank when you open it. Simpler is better IMO, that cap you bought was always their best design.

[@garyalensr]

I love your channel. I appreciate the fact that you make sure your torque pretty much every bolt to speck. In my opinion, it's important but not alot of other small engines mechanics just don't do it. Thank you James for sharing your skills with us.

[@jcondon1]

Thanks.

[@mtcman42]

I've never used a torque wrench. I just turn them 1/4 rotation before they break off. Ha ha

[@JohnSmith-yv6eq]

@@mtcman42 If it does snap off....just back it off 1/10 turn....

[@jimw6991]

​@justjeff4640 First tightening or turning a bolt eventually will create tension. The tension in the bolt provides the clamping force on the parts being held together. Not enough torque causes the clamping force to be insufficient, it vibrates loose when machine is used. Too much torque can strip threads and/or distort materials being joined.

[@lestergillis8171]

The engiine looks like a newer version of the Briggs 4.5 Quantum. My mother bought a new TORO GTS2 back in June, 1995. It has a 4.5 Quantum on it too. My mom passed away in Sep 2020, but I still have that old mower, and it still runs. It got a small piece of plastic or crud stuck in the carb back in May-June of 2005. A carb rebuild kit & cleaning fixed it. It got dirt in it once after that, so I knew what to do. It doesn't have very good compression, after all these years now. But I still use it a few times a year to mow part of a shooting range target area about 12 miles from me. It still gets the job done. I also have TWO spare identical used engiines that also run. When the current engiine shits-the-bed, I will swap out the engiine.

[@esqueue]

I assume a that the original cap vented from those rectangular slots on the bottom outer ring of the cap. This would prevent rainwater from easily entering the tank. Most likely got clogged up due to it having a long passage and the crap that fuel leaves behind. It would be interesting to see if throwing it in your ultrasonic cleaner fixes it up. Again, this is 100% of an assumption.

[@RustyNail5856]

Some times James things like that just slip's pass , no body at fault here, it is just one of those thing's. great catch thou, good video. keep up the good work.

[@nickdavis4049]

Great video! I had the same issue and it took me forever to find the answer. I drilled a couple holes in the cap, and it fixed the issue. However, engine vibration caused gas to spray everywhere. I had to replace the cap anyway. Thanks!

[@oldcrowcornhole]

Had same issue with my B&S quantum. Replaced the cap with same one you did and fixed it. Same issue on our 25 year old snowblower with Tecumseh motor. New cap fixed that too.

[@vk2ktm]

this is an unusual issue, you did very well to find it.

[@zackarymcclain164]

I love seeing you torque every bolt with a torque wrench meanwhile I’m hitting them with my Milwaukee on low.

[@arthurvandelay7677]

Thanks for these excellent videos! I've run into this twice on string trimmers. The first time you encounter this problem, you doubt your sanity because the engine appears to have everything it needs to run.

[@matthiasweigel311]

That's why I finally switched to a battery mower.... Still love my gas backpack blower for the ton of leaves we get in fall but every week mowing is now quiet and reliable....and way less stinky. As soon as good blowers are available in battery I'm switching. But you can take my 2 stage gas snowblower out of my cold dead hands. I live in MN....

[@carljdipietro]

Unbelievable how you figured that out. I've been in that position but had absolutely no answer. I really appreciate you doing this 👍👏🏻👏🏻👏🏻😊

[@allotmentfornovices8256]

Another great instruction video my friend who would have thought that the filler cap was the problem thank you.

[@waltahlgrim5508]

I think the reason there are 2 very different fuel caps listed for this engine is that the original cap is required to meet EPA clean air requirements mostly for the state of California the replacement cap is a noncompliant version. Walt

[@dennisblair1384]

I really appreciate your videos. It gives me confidence I can keep my equipment running, because you describe in your videos the steps you go through when troubleshooting issues. I am also going to (not) read the comments until AFTER watching the video. It can be like reading the last chapter in a book first.

[@jackpatteeuw9244]

I have a very similar mower with an almost identical engine (B&S Quantum) that is over 30 years old. If the weather is hot and you are bagging the clippings and you leave it in the sun when you are emptying the bag, it is hard to restart. If you grab a cool drink, it won't start at all until it is completely cool. VAPOR LOCK !! With electronic ignition on small engines (standard for about 40 years) a new spark plug rarely helps engine performance.

[@jcondon1]

It's almost never the spark plug. But sometimes it is.

[@chrismcgowan3520]

I've been watching your channel for a while as I tinker with generator and lawnmower repairs, I've had a renegade generator sitting for a long time that had me stumped and had a lot of parts and effort put into it, I saw this video and took the cap off when testing it to find I had the same issue, it took longer to show due to the larger tank but after several runs that was indeed the issue, credit to you, an unsellable generator has now past its testing and been sold, your videos have helped on many occassions and it's appreciated

[@jcondon1]

Nice

[@chrismcgowan3520]

@@jcondon1 question for you, I delivered an 8kv generator to a friends farm where he was getting solar and batteries as back up which would also power pumps if needed, the electrician set the power of the solar to cut off the grid power I'm the event of a blackout and wired an earth to the frame of the generator and earth of the generator 240v plug and had it set up to run alongside the solar in the event of a blackout or fire, he just explained simply that this was so if their was a short the solar wouldn't be harmed, I didn't question him further as he was a little shirt on manners and busy, I am wondering if you could explain this in one of your videos, their are other videos about Wether to earth a generator or not (which was no help to this question and not clearly explained in layman's terms), just an idea, love the videos, so many helpful tips in assessing and repairing and much appreciated

[@curtdunlap6818]

The vent on my riding mower slowly got clogged over time unbeknownst to me and caused the same issue. The darn thing would run for 20 minutes that way and slowly lean out! Once I discovered the blocked vent on the fuel cap, loosening it solved the problem, but not before numerous carb cleanings, carb kits and tank cleanings! This had been going on for a couple years, and exhibit itself on hot days too!

[@tristanschaper281]

Wow, in all these years, I’ve never seen an issue like that with a mower gas cap. I’ve seen it plenty of times with portable outboard motor tanks that have a vent screw in the cap, but not those push mower caps. Great video as always!

[@wildefox1478]

Pretty simple and easy fix, that original cap could've been defective, nice work James!

[@jerrybootneck1736]

Great Job finding that cap issue. You'll have it back soon because that pull cord is getting very thin and will soon snap.

[@chrisssmallengines7163]

Great video , showed good trouble shooting methods . Also shows how one thing or system affects the other .This is hard to demonstrate in this field .Thanks again for taking the time .

[@marathoner43]

I have one of those mowers that does something very similar. I will have to try a new plug and a new fuel cap. The carb is good, so I guess that's my next step. Thanks for posting this.

[@er1073]

A fuel cap of all things those are just as bad as the spouts in fuel cans these days. Thanks for sharing your video James. Ed

[@anthonytriolo3643]

Some lawn unit have that feature,you tighten the cap for transportation and release it to unvent It when you start it the tank.

[@John-cb6wn]

You are so thorough best on the internet

[@Rein_Ciarfella]

Thanks, James. I already knew about the failed fuel cap check valve syndrome, but hadn’t seen one of those DIY fuel drain hoses. Just made myself up one and put a length of duct tape around it so there’s no mistaking it’s a tool. I may hose clamp on some sort of wire eye with which to hang it up near my fuel containers. 👍🔧🧰

[@colingraham1065]

Great detective work as always but an easy fix is only easy with hindsight.

[@buckchase1]

Yah, now I also need one of those fancy spark testers! A thing of beauty.

[@RiverratGoRVing]

James as always you have the golden touch. My 1850 Colman Genorator was beginning to act up and after watching your post went and bought a new spark plug and it now runs better had an R in it and ran test and had very low omes. But the gas tank cap was a home run and great to see that you were able to get it fixed that's something that I wouldn't have even give it a thought. Good Job.

[@TheCrittercam001]

Interesting set of issues and excellent detective work in solving all of them♥ Love watching and learning from your videos.

[@brubbelmichi]

That woof at the end of the credits always gets me :D

[@Chris.Y.054]

Jim, great find. My initial guess was a bad spark plug.

[@DeadKoby]

That's certainly amongst the LESS COMMON issues that turn up. It's nice that the outdoor temperatures helped by giving you an audio cue. That's certainly not the first thing you'd think of when you have an issue such as this. Vapor lock was one of my thoughts at the beginning, when I heard it "runs for awhile"...... so I was wasn't way on the moon with that idea.

[@lorrinbarth1969]

I own a mower with a gas cap that has a deep vertical groove cut into the threads. I doubt it will ever fail venting. Any cap with a pinhole will sooner or later plug.

[@rstephe]

Great troubleshooting, but I think you should test further. You can test it my yard. Great vid, as always.

[@johnplump3760]

Jim: I do whatch your videls all the time and do all by own mower repairs. Put a new carb. on a Kohler engine. Engin ran too fast. Found interferance on large carb gasket. Cut a small piece out noy guns great when it starts. I am having the exact same problem. I have to use starter fluid to get it bto start. It does run but needs starter fluid fore every start. I was going to clean the new carberator but you may have saved me much time. Thank you.

[@NY411Info]

The original cap is known to go bad. Probably some emissions garbage. Anyway I took one apart a long time back and I believe it has 2 spring loaded plastic valves in it. With the cap you added I will recommend a in-line fuel filter and tell your buddy do not leave it outside. Water will get into the tank. Nice find btw.

[@davecarlson9350]

Nice catch! As you progressed through your problem solving approach, the cap was the last item on the list. Just goes to show that it's not a common problem, but not one to over look.

[@lmfarms4611]

I had A similar problem with my riding lawn mower. I found that the vent hole was clogged. The wap's had made a nest inside the cap. Had to drill thru the cap to get it to vent

[@AZVIDS]

That was a curve ball (for me). Nice catch. Like the mix of machines you work on👍👍👍

[@briankemp5206]

Great video James! Haven't seen a bad fuel cap in a long time.

[@thomasmagiera3283]

Another top quality video. Thank you Donny. I have come across all these issues with customer machines. the vent problem happens a lot on Tecumseh snowblower caps that fall apart. No matter what machine, what works for me that I advise all my customers to do is keep the fuel tanks completely full at ALL TIMES with premium. Any container left in temperature change will get condensation resulting in water in the carburetor. If the machine has a shut off fuel valve I turn off the fuel and run it till it quits before storage.

[@Maik1968]

Thanks for this video which brings so much information that a ventilation in the cap is important. So: keep on mowing and always a sharp blade 👍🍀🌞😃

[@andybonneau9209]

Gas caps are something that can be easily overlooked and that have a big influence on small engine performance. Maybe something to be added to your future list of things to check.

[@Ronl53]

Great diagnosis and great video. Thanks for sharing.

[@wernerfritsch6436]

15:38 My first thought was: that's pretty little fuel flow.

[@netdoctor1]

I had an intermittent 'no run' one time on a similar engine. That doggone kill wire had laid against the block and burnt through the insulation. It was intermittently shorting out to the block. Tiny diameter high-temperature wire. I had a new one in a box of extra parts.

[@johnbell6956]

I had the same cap vent issue on a motorcycle. Tighten cap - stalled. Left cap loose ran like a champ. Replaced cap - no further worries. Great videos.

[@johnclarke6647]

Most gas caps today are 1/4 T caps. I had to replace the one on my push mower a couple of years ago. If I brushed a piece of shrubbery with the cap side it would come undone and let trash into my gas tank. As I remember it was about $7. Tank vents are a pita on two cycle equipment. I can’t count how many I have replaced on my big Stihl chainsaws.

[@Opinaca]

Got one like that, but It has the good cap. At times I have some troubles with the kill handle....sometimes I have to pull harder on the cable. Thanks for the nice video, very helping.

[@phbrinsden]

Good win. Useful reminder that the cap must vent.

[@PabloDiablo682]

No two items are exactly alike. Great channel. Great work ethic.

[@GrumpyXer]

Had that happen on my JD lawn tractor. After mowing for a while it would die and backfire and it would not start. I would go in the house for a while and it would restart only to do it again after a little while. When I figured it out I just pounded a nail through the hole that was supposed to vent and no more problems. That was 6 years ago and I'm still using that old tractor.

[@dr.e.2008]

Excellent job!

[@richardmorse5307]

I’m having a similar loss of power in my Troy Built with a Honda engine push mower which is becoming more difficult to start. I’ve put in fresh gas, Octane 94, a new NGK spark plug OEM, replaced the air filter, changed the oil, but tipped it once on the wrong side. I’m still puzzled so far. Thank you for your excellent video and diagnosis!

[@stevealaska73]

Great video. Thank you for sharing it. This happened to me a few years back with my riding JD. Stupid cap. I think the vent hole in your original cap is located in the window of the gas pump (diagram)?

[@paulstaf]

I was hoping you were going to take apart the old cap to figure out how and why it wasn't venting properly. May just have dirt in it and needed to be soaked or cleaned. Great video!

[@BruceBoschek]

My Briggs came with the $5 cap and has always worked correctly.

[@kerrygleeson4409]

Same problem brand new truck body builder had crushed the fuel tank breather hose against the chassis thanks for sharing James 🦘👍

[@MrAxelfrom]

I had a similar behaviour on my Toro, eventually I found out that the auto choke was broken. I changed the auto choke and since then the machine works flawlessly.

[@rayshutsa6690]

Thank you James for this one. Something as simple as a gas cap could cause this issue. Great catch James you are very thorough and meticulous it is easy to learn from you. ❤🇨🇦

[@MarkSWilliams27]

Thanks for a very interesting video. I will tuck that in my mind. About the time we figure out all the little tips, tricks, and traps to small engines everything will have gone electric! Good analysis on this.

[@grammardad]

Nice episode. Had a snowblower that would do the same.

[@matthewrichmond5179]

If I am not mistaken most caps are designed to hold pressure to keep the fumes in the tank for EPA/CARB compliance. They also have a one-way valve to prevent vacuum in the tank. Had a pressure washer that did the same thing as this mower. The cap on the tank was able to be disassembled and I found the valve to be similar to a MTD 2 stroke fuel cap. the ones with the little slotted rubber nipple for the valve.

[@FirstSuiGeneris]

I was thinking it might be the cap. The tank wasn’t equalizing! I ran into this problem with diesel heater tanks too.

[@tracysmith6757]

Your videos on this specific mower has been very helpful because I have one of these very mowers, good job!

[@ParrotHead1809]

I never saw a Dremel wire brush before ! That's going on my shopping list ! Great video as usual. Thanks!

[@zrkn1]

I sure learned something new today. I hope your friend isn't leaving that mower exposed to the elements. The cup shape of the top of the cap combined with a vent hole could spell trouble in the rain.

[@AntonioClaudioMichael]

Wow nice find on the Gas tank Cap

[@gman3109]

Had the same thing happen to my Husqvarna snowblower. Would run alright until I got to end of driveway and then sputter and stall, last thing you want to happen during a storm! Cracked gas cap a little bit and would run fine, replaced cap and runs great now!

[@jerryvelders4457]

Great detective work.

[@WarrenKimpel]

I bought a funnel that filters out the water, you might find one to be useful, enjoy your videos

[@BADD400]

Great video James thanks for sharing

[@drunkingsailor2359]

I do the same line of thought,,I usually cut my lawn several times b4 listing it if there's an issue you hope it shows up while in your control.

[@Rev-D1963]

Another truly fine bit of detective work James. I've had this problem in the past; it can be a real toughie to figure out. Thanks again for another fine video. God bless. Rev. D.

[@alialhaidary1072]

@16:00 you were testing fuel flow, I grabbed a cigarette to smoke, but quickly returned the lighter before igniting it fearing the vapor of the fuel to burn. Then I remembered it was only a video 😁

[@Robsenginerepairs]

Nice job James thanks for the video