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Discussion Starter · #1 ·
Hello. The last 2 times i cut my 2 acre lot, literally the last pass each time the engine bog down like the grass was a foot tall and wet. I thought maybe the PTO bearings were going bad. It seem that when i disengaged the PTO it went away. I used the tractor through the fall just not with the PTO, never again bogged. Plowed snow multiple times, no problems. Yesterday put on my 38 blower and after about 40 min the bog came back. This time even with the PTO disengaged. It began to bog while blowing, disengaged the PTO and then went to go forward to drive back to garage it bog down, even when going in reverse. Now im thinking this might be the engine and not the trans. Anyone ever have this prob? It goes away about 2-3 secs after disengaging the PTO or stopping the tractor. Sorry for the lengthy post but this has really got me stumped. Just wanna make sure i tear into the right part. Ive read just about every post on trans tear down, while not to hard very time intensive, but defiantly want to fix it be fore it grenades.
 

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It sounds like a carb or governor problem. Carb problems can come and go with weather changes until they get really bad. First thing I would do is give it a good in place cleaning, check all the external screws/mounting nuts for tightness, check all the adjustments, and replace the spark plug.

If that does not fix it, might be time for a carb rebuild.

Sheldon
 

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Discussion Starter · #3 ·
My mistake. When i said bog down i meant to say that the engine started chugging, its at full throttle but doing alot of work. Not like it was just slowing down. It runs great, other than after everything is really hot this problem presents. I use it alot for pulling a small trailer and getting firewood and such. ITs only after using the PTO for awhile that this starts. Thanks for the quick reply.
 

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Might be water in the gas. That would do it. Drain the bowl and capture the remains. If water is present in the bowl, then drain the tank and clean the carb.

Might be fuel starvation. Change the fuel filter and check the screen in the tank for dirt.


This happens to be Oklahoma gas that I drained from an 8000 tank yesterday. Why is OK gas significant? No ethanol. In the area that I picked up the tractor from, all of the gas stations had pure gasoline. The water is due to condensation.
 

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The 12 hp Kohlers usually have a coil. It is possible that the coil is bad but that would be pretty rare. I would put that at the bottom of my list of things to check/change. Usually when a coil fails thermally, it is as if the key is shut off. The wrong coil installed will cause it to overheat and that gives all manner of symptoms.

The key to narrowing down the cause is to see what causes the engine to stop losing power once it starts. If just letting it idle for a minute while cures it temporarily then I suspect fuel starvation. That could be anything from a bad fuel filter, bad fuel line, or dirt in the tank or some other related issue. If it occurs at completely random times, then I would suspect something in the tank like sediment.

It might even be the points. I have seen that before. The points were misgapped and when the points got hot, the metal would expand and then the points would not open.

If it were mine, I would replace the condenser, clean or replace the points, and drain the bowl and replace the fuel filter. I would also drain the tank and blow it out and give it some fresh gas. All that is cheap to do. If the issue persists, then I would start looking at things like wiring, coil, valve lash, etc.
 

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Discussion Starter · #8 ·
Theres no safety switches. I initially thought was air fuel prob. I took it all apart and adjusted it, although didnt drain fuel. By the way WOW thats alot of water in your fuel. I use this thing alot so if gets fresh fuel often. It sounds to me like a bearing might be seizing somewhere. But after looking at all the manuals online i cant imagine which one. it does it high, low, and now after it started with the pto on, even with it off, but only when you put a load on the engine. If i run it at about 3/4 throttle its less noticeable but still there. Defiantly worth taking the carb apart and draining the gas before going any further though. Just doesnt seem like carb prob. hope it is though.
 

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My mistake. When i said bog down i meant to say that the engine started chugging, its at full throttle but doing alot of work. Not like it was just slowing down. It runs great, other than after everything is really hot this problem presents. I use it alot for pulling a small trailer and getting firewood and such. ITs only after using the PTO for awhile that this starts. Thanks for the quick reply.
Runs great until hot, id say coil if it has one possibly easy check. It's only after using pto it starts, with pto on does it die if you try to get off seat?
 

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Discussion Starter · #11 ·
It doesnt seem like a loss of power more like something is binding up. Didnt really consider a points condenser coil or timing prob. although that would cause it to run rough as **** with a load on it. Thanks for all the input. looks like a trip to the store for parts before it snow this afternoon.
 

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Discussion Starter · #14 ·
Well I finally figured out the problem. When i tried cutting grass this year the bog or break up was even worse. I ended up changing the muffler, spark plug and wire, points, condenser, fuel, filters, fuel line, took the head off to check for carbon and look at valves, set valve lash, used a timing light to set points. All for not. Still broke up when got hot and put under load. Then changed the coil and it runs sweet. Not one burp from it now. I never would have thought it was the coil. Oh well at least it got one **** of a tune up. thanks for all the replies.
 

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thanks for updating us on this. I have a similar engine and always appreciate an issue being resolved for the benefit of the forum. I very briefly owned an old Mercedes wagon that had a similar problem with the THROTTLE MOTOR. Yep, had a motor for the throttle. Anyway, it would get hot, start stumbling, and then just quit. Let it sit for 30 minutes and you could get up and drive away. Was $900 for throttle motor. I sold it.
 
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