Piece of Junk Kohler part II


LawnSite Member
Nice to be back here on the site. I have been gone for a couple of weeks due to my wife giving birth to my daughter.

Anyway this Kohler 25hp is giving me more trouble and I need help before I throw it into the river. It will start and run fine and then all the sudden it will start running rough. It will pop and spit and then all the sudden it will clear up and run fine. It might run fine for two hours or two minutes, who knows? I have done everything I know to do; changed the plugs, changed the air filter, changed the fuel filter, removed and cleaned the carb, drained the gas tank, checked the compression on both cylinders. Anyone have any more ideas? I thought that it might be the coils but then I thought that if it was the coils then it wouldn't clear up once it started, would it?

Any help would be appreciated.

I would pass out cigars but that might be a little hard!!


LawnSite Silver Member
How many hrs our on it? I have a 20 hp Kohler on my Grasshopper that is doing the same thing. Mine has 2500 hrs
and has been doing this off an on for the last 500 hrs.
I was going to put a new carb on it but decided to hold off.

It uses just a little oil, but I figured it was time to replace it, so I am just waiting for it to blow up.

Let me know if you figure it out.


LawnSite Member

The motor only has 350hrs. on it.


I've already changed the fuel filter and blew out all the lines and drained both tanks. What will the gas treatment do? I value your opinion so give me some more ideas.


The last time that I had a problem with this motor you solved it so chime in with your diagnosis.


Kohler has problems with coils. Several serviuce bulletins out on the subject. There is a new part number that supersedes the old ones in service on many of these engines and it is my understanding that Kohler will supply the new coils at no charge, not sure if that will apply to installation or not. Also a critical adjustment in the air gap between coil and flywheel. I have two new coils sitting here for my 25 hp horizontal, now that mowing has slowed some I'll pull the engine and check numbers and adjustments and if I have the bad coils I'll swap them out. I'd be willing to bet that your problem is not fuel, it's spark. Talk to your Kohler dealer about service bulletins dealing with coil problems.


LawnSite Fanatic
N.E. Wisconsin
My favorite subject.
My firsthand advice from someone who owned one is to get rid of it.
That said there are MANY things you can check.
1. Ignition switch.
2. Head gaskets
3. Intake gasket.
4. the dreaded coils
5. fuel filter
6. fuel pump
7. Oil pressure or head temp sensor
8. search this site for Kohler.

When all else fails with this hell motor go back to my second sentence. My first Kohler was spawned from the devil himself in 1998. I almost had more mechanic time than mow time.
Hate to be the bearer of bad news but I think some of the assembly people were working on these engines after a long night out. Good Luck.

Eric ELM

Husband, Father, Friend, Angel
Chicago, IL USA
Sounds like a broken wire somewhere that is making contact at times and not at other times. The only problem I've had with my Kohler is the intake manifold gasket at about 2,200 hours and I had two modules replaced at around 3,000 hours. It could be a bad module that has a bad connection too. Try cleaning all your wire plug in connections and then coat them with electrical grease to keep them from coroding. If that don't do it, you may need to have to have the dealer check the modules in it. They can check them to see if they are bad. If it only has 350 hours, it should still be under warrantee. It has a 2 year warrantee, so it can't be to old with only 350 hours. I now have 201 hours on the new diesel DC I got in June. I hope this helps. :)


LawnSite Senior Member
Central Florida
Might be a long shot, but if it's a ZTR, check the safty switch under the seat.May need to be adjusted.


LawnSite Member
Thanks guys

I believe that the problem is probably electrical. I'll check all these things in the AM. Thanks again.