How to diagnose a lawn tractor that bogs (and dies) when the electric PTO is engaged

[@kbssmallenginerepair2615]

It was pointed out that the engine would pull a vacuum on the intake stroke instead of drawing in a fuel mixture therefore having nothing for the piston to "compress" causing a low compression reading. After doing a little experiment and testing of my own, I found that to be absolutely true. This was simply just a case of extremely loose rockers from lack of maintenance (never having had a valve adjustment with 500+ hrs) and having the push rod simply fall out of place. I did a valve adjustment on both cylinders and now onto the next one...

[@RaleysSmallEngines]

Awesome, what caused the push rod to come out? Or did I miss something.

[@mattt4183]

It's the intake valve that wasn't opening. The engine will just pull a vacuum on the intake stroke instead of drawing in an air/fuel charge. So there's nothing in the cylinder for the compression stroke to compress hence the low compression. If it was the exhaust valve not opening that wouldn't cause low compression but the intake valve definitely will. Interesting that you said the plug was wet, but didn't say what it was wet with. I'm guessing oil rather than gas? Did you smell the plug or just look at it. Either way it was a good call to pull the valve cover instead of performing a leakdown. Leakdown would've passed and then what..........

[@kbssmallenginerepair2615]

@@mattt4183 You, kind sir, are absolutely right. Thank you for sharing your knowledge! Honestly, while I couldn't quite wrap my head around all of it, I did a little experiment today and found it all to be completely true. Today was a great learning day and I am grateful for your input.

[@Dangbo3030]

Those grease fittings on the spindles are not functional on these mower decks. The bearings are on the top and bottom of the spindle and they have rubber seals that prevent grease from getting to the bearings. Also these v- twin motors need to have the valves adjusted adjusted after so many hours. Great video

[@Thomas-ul3uy]

I have a Husqvarna 26hp Kohler with 54 inch deck and it shuts down when engaging the electric PTO. Did replace the coils, one wasn't firing. I removed the electric PTO clutch, turns freely, checked it with OHM meter, it checks fine. I checked the gap on the clutch and need to readjust it to .018, thought clearance spec was .015. Can't find any binding on deck pulleys. None of the bearings in idler pulleys don't make any noise, the blade mandrels were cleaned and repacked with grease. All turn freely. When engaging PTO, sometimes it kills engine, sometimes it keeps running, choppy RPM/ runs rough and I get smoke from the belt at electric PTO clutch. Just think it is odd that PTO clutch checks with 3.2 OHMS. I even popped the caps from the bearings on each side of clutch and packed grease in bearings. Would you know of anything that I'm missing?

[@fivepointeightnate]

I have the Ariens 46" 22hp doing exactly the same thing. They are almost identical mowers. I bet you just figured out my problem before I got to diagnose it. Thanks for getting footage of your issues!

[@timpmuldoon736]

I fully agree..😂 My Husqvarna YTH28K46 is 6 yrs old still looks fairly new.. I use it 2 times weekly for 7months out of year.. I guess $$ is not problem for this owner .. lawn equipment isn’t actually cheap..!

[@ranjanty]

HI KB so glad I found your channel. I have the 23hp with the 48in deck. I have 795 hours on mine and I just started having the same problem. I subbed. Yeah the guy got lucky. 18 months ago I found my pushrod in the sump pan. I fixed all that and in the process I broke a bolt off on the cover. Thank goodness I was able to fix that too. I was hoping the switch was going bad on mine because sometimes it would cut for about 15 min then it would shut off. I think I will pull the valve covers off first. Thanks for the video.

[@BrianHoff04]

Hi KB... great video. I fix riders very part time & often a problem is brought to me that is unique to me (haven't seen it before). I might do 30 mowers in a year and that's how I learn. I typically hunt down videos to see the diagnostic habits just to give myself some sense of order. You, Taryl, Musti, and some others. All of you do a great job providing some insight / advice on how to diagnose. Just in case it helps... Taryl has a video about bogging down & in his example the coil was providing a weak spark.... his tester is one of the old fashioned ones. He replaced the coil and it ran great. Some other guys also show that a weak spark is a possibility so I try to keep that in mind when I see an issue like this. Glad it was just the valve adjustment and that your repair did the job. Thanks for the video.

[@michaelm2725]

It's two years later and I'm in the same boat. I work full-time and enjoy repairing riders on the side. KB, Taryl, and a few others have been an amazing resource. I hope you guys are having a good mower summer so far!

[@amandacarter6916]

So... was this fixable? I'm in the process of trying to diagnos my mower.

[@bertgrau3934]

​@@amandacarter6916 Yes, replace the push rod, adjust the valves, I would adjust the valves on both sides not just the weak/dead cylinder. By the way, he could still use the original push rod. He didn't show how to adjust the valves, but there's lot of good videos to show how. Good luck.

[@dinamat5963]

Owesome video, my Cub Cadet 1152KW, Kawasaki engine is bogging to the point of stalling, ill check the compressions and valve set up tomorrow, thanks for your so easy to understsnd to the point video.

[@FarmerGuy-1]

Nice to have an easy fix come through.

[@kbssmallenginerepair2615]

Thank you sir! It's always nice to find the problem fairly quickly.

[@bigsonslawncare]

I'm saving this one have 2 of these engines, And this had me stumped, I thought deck also at first. Good recover!

[@kbssmallenginerepair2615]

Thanks Big Son's. They can be tricky sometimes for sure. Apparently this is common on these, so stay on top of your valve adjustments.

[@bigsonslawncare]

@@kbssmallenginerepair2615 Gotcha💪🏽

[@RaleysSmallEngines]

Most likely it's a valve seat came loose in head and cooked sideways holding valve open, causing pushrod to fall out and low compression. Great video Kyle

[@kbssmallenginerepair2615]

Thanks T-Bone. My mistake on explaining the low compression with a closed valve 🤦🏻‍♂️. I actually went to make an update video and there was no leak down! Decided to install the push rod and recheck compression. Perfectly matches the other cylinder and runs great…🤷‍♂️

[@HappyOldDogAndCatFarm]

@@kbssmallenginerepair2615 Did you video that fix too?

[@goosecreeksouth9327]

I heard it the first you started it . I have had a bunch of those do that due to not servicing the valves every 100 hrs . Good video

[@kbssmallenginerepair2615]

Thanks Goosecreek! This is the first one I've seen this exact problem on. Thanks for sharing!

[@philliphall5198]

Thank you for information and advice Merry Christmas

[@philliphall5198]

Merry Christmas and Thank You’ll for information

[@davidarnold344]

Mines bogging /knocking and puffs some smoke when I engage. But seems to run strong. Should I check my push rods/rockers?

[@TheLawnmowerLady]

Glad you zeroed in on the problem so quickly. Definitely could have gone way down the rabbit hole trying to figure this one out: rings? coil? valve seat? con-rod?

[@kbssmallenginerepair2615]

You are absolutely right, this could have been a major headache for sure! Thanks for stopping in!

[@kiesha104]

Good call... I always get the mice nest motors... overheat wipe out the cam and seize wm up...

[@Mac210.]

Good video KB.

[@kbssmallenginerepair2615]

Thanks Mac!

[@butler386]

Very helpful diagnostic process. Should not be a real hard fix. Get it done and show us how you did it. Thanks for the video.

[@kbssmallenginerepair2615]

Thank you! It ended up just being very loose rockers from having never been adjusted. At 500+ hrs, they were definitely due. I adjusted all the valves on both cylinders, and away she went!

[@chrisezelle]

👍🏼😀🌞

[@paulrhodes482]

Thanks buddy for another amazing video! Have a blessed day.

[@kbssmallenginerepair2615]

Thank you Paul! Have a great day yourself!

[@Smalltechguy]

First time finding your channel. I'm going through the same issue on a Kohler Courage 26hp. Comp is 180 on both cylinders. I'm sparking on both as well. I had to replace the coils though being that it was only firing on 1 cylinder at the start of this project. Valves are set correctly and the govener is also set right. This mower deck just bogs down. I did take a tach reading which was in the range of 1400. A very puzzling engine on this husqvarna.

[@burnitout96]

What did you do to fix it? Adjust the valves? I am having the same problem with the same engine, not even 2 years old.

[@cateward7043]

Love this video!

[@biggaspirit1]

Enjoyed the video and learnt, thanks.

[@kbssmallenginerepair2615]

Excellent! Glad you enjoyed, and got something out of it!

[@dr.lmsb4456]

Awesome video brother ... thanks for sharing . Cant wait for the next one . Take care and stay safe .

[@kbssmallenginerepair2615]

Thanks Doc! Hope you had a great night kid free! 🤙🏼

[@dr.lmsb4456]

@@kbssmallenginerepair2615 actually one of the twins got sick and we had to cancel it ... shes doing better but not out of the woods yet . But thanks for checking in . I do appreciate that .

[@kbssmallenginerepair2615]

@@dr.lmsb4456 oh man, sorry to hear! Hopefully she gets better soon. Having sick kids is never fun!

[@dr.lmsb4456]

@@kbssmallenginerepair2615 thanks brother , i hear ya

[@juanitaj5248]

was sold a "fully serviced" Toro lx 500. Well it bogs to the point it wont move, has a whining sound & then the gas peddle goes limp with no spring back. . I could smell belt , or something of a similar at one time as well. Any advice would be greatly appreciated.

[@TheRustyRooster]

Good video KB... Let's think about this a sec. Push rod is out of rocker, so valve is always closed. Humm yet you have low compression. Ya might better do a leak down test and make sure that valve seat didn't come loose. I'm curious to know what ya find.

[@RaleysSmallEngines]

Yep seat came loose

[@kbssmallenginerepair2615]

Thanks Rooster. My mistake in explaining there is low compression with a closed valve! 🤦🏻‍♂️. You are absolutely correct, thanks for pointing that out. I went out to make an update video, and there was no leak down! I’m wondering if I had a bad connection or got a bad reading on my original compression test. I decided to throw the push rod back in and check compression. It perfectly matches the other cylinder and now runs great…

[@mattt4183]

Copy and paste of part of the response I left to KBs pinned comment. It's the intake valve that wasn't opening. The engine will just pull a vacuum on the intake stroke instead of drawing in an air/fuel charge. So there's nothing in the cylinder for the compression stroke to compress hence the low compression. If it was the exhaust valve not opening that wouldn't cause low compression but the intake valve definitely will.

[@kbssmallenginerepair2615]

@@mattt4183 Absolutely true. Thank you for sharing!

[@healthyamerican]

i have this tractor, husqvarna lgt 2654, but has the kohler 7000. it bogs down or stalls when engaging pto when the engine is cold. but if the engine is warmed up first, then it doesnt bog or stall when i engage pto. any suggestions? i replaced fuel filter, checked the belts and spindles which move freely, replaced the voltage regulator, cleaned the pto connector and seat safety switches with electronic spray, removed spark plug wires and did not have engine stall. any help would be appreciated..ty

[@Art-jl6pt]

Thx adding to my repair list

[@SCouch-cw6je]

I have a 27hp Kohler on a toro zero turn that bogs and I can not figure what the problem is. Charging system is working correct, carb is clean and replaced. The mower was flooded recently. It starts idles and runs great

[@dominicdziurda4505]

I have a dty4000 mower and I just put a new clutch on and now I'm having a bog issue when I start to mow.

[@ATCRyderX]

That Spark Tester - Where? What? All that. I need it.

[@WhizFlipper]

John Deere la145 same engine same issue thanks for the video

[@JamesKain]

Thanks for the guidance

[@cosmicwarrior62]

I have a Kohler that starts to flood out, when the PTO is engaged and you hit a rut in the yard. The engine will die and will restart with ease. I'm looking for an electrical problem, since the carb has a fuel shut off valve.

[@fergusonto-2032]

How’d you fix it , just replace valve rod or did you have to tear motor down ?

[@stephenpiersa8377]

Hopefully someone can help me, i have a john deere e130 which lost power while cutting the grass. When you engage the blades, the engine, instead of a higher output, the engine drops down lower and very little wind coming out of the chute. Even when starting it up, the engine drops down, seems to have low to no power.

[@Mder1234]

What if you weren’t getting spark ? Any ideas what would be wrong ? Bad coil ?

[@francislang5075]

back in july i replaced a magneto on my harqvarna. had a problem something like that. is ok now

[@kbssmallenginerepair2615]

Interesting. If there is no spark and it is not firing I would imagine it would be the same situation. Glad you figured it out!

[@cjsawinski]

Mine has plenty of power but after a little bit of time the power will drop… I’d say about half hour of mowing really tall and thick stuff… which I used to be able to plow through the tall and thick stuff all day… it fires on both cylinders for sure. Only problem I can seem to find is it might have a little leak on one of the valve covers… I think it’s just getting hot and loosing power, but in years past this has never been an issue… there’s also no nests in the engine, I’ve pretty much covered all the simple stuff lol

[@TKO-NY]

Any update?

[@cjsawinski]

@@TKO-NY not really, just changed the oil and put a new air filter on it and it hasn’t been a problem since… but it’s also been pretty dry this summer (other than in the spring), so my grass hasn’t been real thick and wet since spring… but basically I think it’s solved with the oil and air filter

[@TKO-NY]

@@cjsawinski thanks!

[@NewJerusalemTimes]

It looked like the rocker arm mounting stud walked its way out a bit, causing the valve lash to get too sloppy, thereby dropping the intake pushrod. It happens.

[@sunsmile57]

HELP, my tractor was running fine until a bad knock started. What I discovered is the vibration loosen one screw on carb and it got shucked into engine. What can I do? Where do I start to fix this??

[@kbssmallenginerepair2615]

Your best bet would be to pull the head and look at the damage the screw caused...

[@philliphall5198]

Use 222 lock tight on carb screws. AllWAYS

[@rockd8946]

Well done 👍👍

[@jjuggernaut3218]

I had a floater on the same engine. I guess a sleeve that was peend in came out as well. Which caused which I have no clue.

[@colemant6845]

Great video... I have the exact engine and similar problem on my John Deere... except my VTwin bogs down completely (stalls) when I let out the clutch. It will do this even with the transmission disengaged. Replaced the fuel Pump/filter and lines thinking this might be the problem. Still stalls out. I did your spark plug troubleshoot and both cylinders kept running. Now I'm stumped! What would cause the engine to stall when I let out the clutch?? Thanks!

[@kbssmallenginerepair2615]

Without seeing or hearing it, my first thought when reading your description would be a safety switch. If it stalls or dies even with no load (with the transmission disengaged) that would lead me to believe a seat switch, or brake switch is bad or failing. Does it bog down like there is a load on it and slowly die, or shutdown like it is being turned off?

[@danielgilbert4553]

That’s what I was going to say sounds like a safety switch on the seat or brakes maybe just unplugged

[@jamesphillips9272]

@@danielgilbert4553 hell yes! Thanks dude!

[@LNRRidez]

That mower was very similar to my old one. Sorry I haven't been around lately, life has been grabbing us by the horns this past week or two.

[@kbssmallenginerepair2615]

It's all good brother, take care of yourself and your family. Thanks for stopping in though! Hope you are doing well otherwise!

[@brandonyoung7760]

Nice video. Is it best to engage your blades at low idle or full idle?

[@joebird1400]

Full

[@JungleBobRepair]

Good job Kyle!

[@kbssmallenginerepair2615]

Thank you my friend! Hope you are doing well!

[@prepertruckin8525]

⭕️after this much time has passed... are those good engines? (provided proper maintenance was or could be done)

[@spike2794]

My husquevarna with a Kohler Engine is doing the same thing. must be a common problem with them.

[@paulleblanc4653]

My identical mower had a misfiring coil when it got hot,

[@Colin56ish]

All of these "V" twins have a reputation for loosening valve clearance, especially on the Exhaust. Mechanics should always check the clearances so you can get an idea of what has been going on.

[@scottseal418]

Valve cap is missing as well

[@danielgilbert4553]

Did you fix the mower?

[@kbssmallenginerepair2615]

Yes I did.

[@RaleysSmallEngines]

Pop off the head remove valve. Ping seat into head with center punch and fire that puppy up. 😆 🤣

[@francislang5075]

good job done

[@kbssmallenginerepair2615]

Thanks Francis!

[@normanschupp485]

Those engines are known for exhaust valves seats coming out

[@rogermcdonald1607]

Nice diagnostic video KB. i wonder how long he was running the tractor that way. Thanks for sending me your sticker KB. It looks great on my board👍🇺🇸 Roger

[@kbssmallenginerepair2615]

Thanks Roger! Glad to help in filling your board up! From the sound of it, he had been running it like that for a while. He had no need for any more power and it sounded just find to him...

[@donnielaurie3232]

From Don's Small engine repair reach down and grab the valve cover if it is cold it is not firing on that cylinder you can have a spark plug not firing even though your spark plug tester says so does the first thing I do if it sounds like it's not running on both cylinders reach down and grab the valve cover if it is cold is not firing

[@pointbreak8293]

Nice video KB… 👍👍👍

[@kbssmallenginerepair2615]

Thank you my friend!

[@pointbreak8293]

@@kbssmallenginerepair2615 yes sir. Awesome channel man. Keep them great videos rollin…👍👍👍

[@philliphall5198]

Coil or head gasket

[@philliphall5198]

I expect it on a dirty engine It’s very common on no cleaning and not removing covers

[@johnstrange4567]

Doesnt look like the owner spends much time cleaning thay mower. More than likely the shroud is full of grass and a mouse house so that cylinder got hot, floated the valve stem sleeve which caused the valve to hang up and drop the push rod. Common problem in aluminum heads

[@donl3159]

Hey KB, new subscriber and extremely grateful for fellas like you that help us along with some of our issues! I have a 24HP Kaw on a 48 ZT. HD Gravely. Noticed a power drop from yesterday to today. Belt squeals when I first engage PTO, and mower bogs down when in thinker grass. When pulling plug wires, I only notice a little sputter and missing on each side. Any direction you can point me in? Repair shops are backed way up, and I can’t afford a huge bill either. Any help would be appreciated from anyone honestly

[@110americalovingpatriot2]

Real men pee on the plug wire to make sure it works 😝

[@robertflanagan6117]

I would expect a head gasket bad

[@mikeevery2459]

It will be the head gasket!

[@philliphall5198]

Needs a seat cover pretty bad to Yep check cly firing first thing Probably broke push rod

[@brunopascal3793]

Not meaning to be rude but what is the point of pulling out the spark tester and the compressor tester, view or read their results without explaining what the results mean. Are they close to normal, are they abnormal... You don't say... You simply move on to other stuff.

[@oGERONIMOo]

👍

[@RandyStinnett-t4e]

Change oil

[@joyubinas8616]

Please go directly to the what, why and fixing alternatives!🤦🏻‍♀️🤦🏻‍♀️

[@henrymurawskibigdogrepair]

Value cap fell off

[@gumbootcloggers8330]

Studs backed out of the head.

[@Dee-hi5zj]

I mean - come on... the guy buys an expensive yard machine and takes the deck off and tosses it out to the elements for a few years... Small tarps are CHEAP compared to shop rates! Some people have their head so far up their ass they can't hear their alarm clock ring!

[@Herman-nk9fi]

Ii