Kohler CV13S quits under load

[slo jim]

Friend said his Kohler CV13S 21526 runs for about 10minutes and then quits. He suspected carb problems. I suspected ignition module. Could not duplicate the problem. Ran for 30 or 40 minutes in the shop and only ran a bit rough. Then put it under load by putting in gear and activating the mower. Then it started to run very rough and acted as though fuel starvation. Then it quit. Restarted immediately, but still ran very rough. Got it back into shop , but just barely. Would not rev up to speed and still sounds like carburetor problems. What is the next step? Does this sound like ignition module to anyone? Fuel pump? Clogged fuel line? Any suggestions are welcome. slo jim

[Luffydog]

Do a compression check on it first. Then if all good start it up and pull one plug wire off if it kills the engine you know you have a cyclinder down. The one you pull off you know is dead but should run on the other. If it doesn't die repeat with other side. If it does take air filter off start it back up this time with a spray bottle of gas see if when you spray it into the carb to see if it stays running. If it does you have a carb problem. Easy test

[Skywatcher]

Hi Slo-Jim

In situations like this, it helps to indicate on what machine the engine is mounted. This will give us an idea of the fuel system supplying the engine. For Example. The John Deere LT-133 has this same engine that has shown the same symptoms. Problem can be caused by a dead fly in the fuel tank.

The fuel is pulled up through a dip tube and round a 90º bend. If a fly gets pulled up the dip tube, it can't go round the corner so severely restricts the fuel supply to the engine. Once the machine is shut off, the fly settles back into the tank until next time which could be 5 minutes or 3 hours. As I say, this is just an example of how the engine can be immediately blamed when it has nothing to do with the engine. Let us know what you find. All the best,

Sky

[KE4AVB]

Do a compression check on it first. Then if all good start it up and pull one plug wire off if it kills the engine you know you have a cyclinder down. The one you pull off you know is dead but should run on the other. If it doesn't die repeat with other side. If it does take air filter off start it back up this time with a spray bottle of gas see if when you spray it into the carb to see if it stays running. If it does you have a carb problem. Easy test

Luffydog, It will be very hard to pull more than one plug wire it is a single cylinder engine.

And as Skywatcher noted it is most likely on a JD and spec is more likely 21525 instead of 21526. Kohler doesn't list a 21526.

Skywatcher, Got those big horse and cow flies there too? Has happen here with a bumble bee except it was a Craftsman rider.

This is one those divide and conquer problems. It is loading related problem so the carburetor definitely can cause this as well as the fuel pump, plugged fuel filter or supply line, and even a bad spark plug. Plus a worn out engine with low compression can cause this. Some these problems are not easy to fix and only way is test each possible area until the problem goes away. I would start by changing the fuel filter and cleaning the carburetor and work from there.

[bgsengine]

also make sure and check the shutdown solenoid and make sure it is getting power to it whenever key is on - had one some time back that was traced to a bad key switch - ran fine for a while then started doing as you described - the key switch was losing contact and 12v not getting to backfire solenoid.

*edit* - especially because certain of those kohler engines had solenoid problems - they have a complete service kit to replace solenoid, change the wiring and install a heat shield and insulator behind the carburetor to resolve that bad design issue.

[slo jim]

Thanks for the replies and sorry for the wrong number. It is series 21525 and is mounted on a Deere LT 135. I will go deeper into the fuel delivery system and report findings. Other than singing the Shoo-fly song, how do I get a fly out of the tank without pulling the tank? The bad thing about these fuel tanks is that you cannot even look down into the crazy thing.

[Skywatcher]

Hi Jim

Yes these fuel tanks are a bit miserable to work on, Disconnect the fuel line at the fuel filter and use about 10 psi max to blow the fuel line clear back to the tank. Take a length of clear flexible hose lice PVC hose. This hose will have a natural curve baked in from when it was wound onto the reel while still warm at the factory. Park the tractor on a side hill with the fuel cap on the low side. Hold the hose so it curves down then work it through the filler and into the tank until you feel it hit bottom. Without letting the hose rotate, start a siphon and get the fuel out of the tank. Hopefully any flies or other debris will come out with the fuel.

Always use a strainer funnel when fueling these units. That being said, I once was fueling my JD LT-133 through a strainer funnel and a stupid fly flew into the open fuel tank right beside the funnel. Machinery on farms usually have the most problems as flies get into the end of the bulk fuel tank nozzle, then straight into the machine's fuel tank. On my customer's service reports, I'll often list the contents of the fuel tank just for a bit of fun. Hope this helps,

Sky

[Luffydog]

Sorry it was late I didn't look at the numbers that close. I just thinking about the problem not the engine. Sorry for the mistake. My fault

[slo jim]

Thanks Skywatcher, really helpful replies. I will get to work and let you know what I find.

[slo jim]

Thanks to everyone who chimed in on this thread. Problem solved. No bees or flies. In California, we have earwigs…they are everywhere. One made its way into the fuel system and plugged the line and filter. I love siphoning gas through a tube…always get to eat some and justify flushing with a cold beer. Thanks guys. slo jim