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Discussion Starter #1
I have a craftsman with the Kohler motor and it will run strong for about a half an hour while I’m mowing and then all of a sudden it drops in power and doesn’t keep the revs up
It occasionally with kick back in for a min but then drops back down
Does anyone know what this could be??
I cleaned tre air filter and the gas filter was replaced a couple years ago
 

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Sounds like your timing may have slipped. Do you notice that the engine is hotter than it should be?
 

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Sounds like a fuel delivery problem. Remove gas cap and use either a compressor or a can of air to clear the tiny hole in the center of the cap and diaphragm under that. Take a look inside the tank to see if there is anything that could obstruct the flow. Gas filters should be replaced at least yearly, or sooner depending on the gas used, especially if you use ethanol gas. Take the hose off after the fuel pump and ensure you are getting a flow of gas when cranking.
 

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I've had 3 or 4 kohler CV singles do that and it has turned out to be the coil most of the time. The best way I've found to check them is with a cheapo HF inline spark tester. One of mine would quit after a round or two of mowing then crank back after a few minutes, I was sure it was fuel related but when I put the tester on it after it died there was no spark.
Cannon
 

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I've had 3 or 4 kohler CV singles do that and it has turned out to be the coil most of the time. The best way I've found to check them is with a cheapo HF inline spark tester. One of mine would quit after a round or two of mowing then crank back after a few minutes, I was sure it was fuel related but when I put the tester on it after it died there was no spark.
Cannon
Absolutely! But it is still a good idea to check the gas flow if that hasn't already been done. The fuel filter that was several years old bothered me.
 

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Coil issues would definitely affect timing and do behave erratically when hot.

If it were a fuel issue, it would cause the same type of problem whether cold or hot.
 

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Coil issues would definitely affect timing and do behave erratically when hot.

If it were a fuel issue, it would cause the same type of problem whether cold or hot.
One often overlooked item with fuel is something partially blocking the fuel outlet. The motion of mowing may cause that something in the tank to partially cover the outlet. When the tractor is turned off and still, the obstruction moves away. Ensure that you have fuel flowing, then move on to other causes.
 

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Discussion Starter #10
To try and describe it sound and feels like someone is pulling the throttle down about 3/4 and stays like that and occasionally it will kick in to full for a second and then drop down
 

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If this is a gravity feed fuel system definitely check for fuel flow. I had one that worked fine for weeks and then one evening quit while coming up the drive. Plenty of gas in the tank and nothing could be seen in the tank but when I pulled the fuel line NO GAS !! When they drilled the hole in the hose barb on the bottom of the tank a swirl of plastic was left in the hole and some tiny bits of crud finally stopped up the hole. I took the correct sized drill bit turned by hand and cleaned out the swarf.
 

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If this is a gravity feed fuel system definitely check for fuel flow. I had one that worked fine for weeks and then one evening quit while coming up the drive. Plenty of gas in the tank and nothing could be seen in the tank but when I pulled the fuel line NO GAS !! When they drilled the hole in the hose barb on the bottom of the tank a swirl of plastic was left in the hole and some tiny bits of crud finally stopped up the hole. I took the correct sized drill bit turned by hand and cleaned out the swarf.
Sounds like you need a better fuel filter to inspect flow through. I generally use these two types for that reason, even if there is an in tank filter.
 

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Discussion Starter #14
Update
So there’s a couple thing I forgot until I used it today
First thing is as soon as it kicks down there is a serious smell of fumes like it’s running super rich
I ran out of gas tonight and when I filled it back up it ran perfect 100% for about 20 minutes until I had to come in from lightening
Up until it ran out of gas and I refilled it about half a tank it was running terrible for about an hour.
Maybe these details will help a bit
I did try cleaning the gas cap earlier too but no change from that
 

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Advance(spark), fuel, air.

You need to think about what is happening. Your fuel is a constant (assuming you checked the filter), that leaves your air filter getting clogged or your timing changing.

Look at your air filter and measure your coil, after that you need to pull your flywheel and inspect your key for cracks.
 

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I doubt timing is changing. It may misfire though. Have you had carb bowl off? Any mower that sat for years likely needs a carb cleaning. You may have crud in bowl that is causing float needle to not seal and then a flooding rich condition.
 

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Which Kohler engine? Does the fuel line run inside the shroud, from pump across the block and then to the float bowl inlet? Does this happen more often on hot days?
If any of the above apply, try running with the hood removed. If that helps, you may have some fuel percolation going on that will have definite effect on how the engine runs.
tom
 

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Discussion Starter #19
Still doing it
I did notice it was cooler out the other night and it ran at full power for much longer than normal before the problem began
It’s weird how instantly I smell the excessive fumes when it kicks down likevthat
 
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