2300 series 18hp kohler acts like out of fuel once warmed up

[greynold99]

Rivets,

I think you may be on to something with the looking for a crack or loose fitting hose connection in the fuel line somewhere. The fact that once the tractor cools off and then starts right up for another hour or so of mowing would suggest something heat-related... Plus the fact, I've already replaced the ignition coil would to me be more reasonable than a carb-issue.

When you talk about the 'pulse line' which section of tubing are you referring to? There seems to be 3 sections: flexible rubber/pvc tubing from gas tank to fuel pump; a small section of tubing connecting the outlet-side of the fuel pump to metal-tubing that goes through the engine section (under the cover where I can't see) to a piece of flexible rubber tubing on the opposite-side where the metal tubing comes out to the carburetor.

Also, it's interesting to me that there are at least 3 other issues being reported on the forum with similar issue for these Series 2000 Cub tractors of the about the same age.

Thanks for replying and sorry I didn't pick back up on this to respond earlier.
Greynold99

 

[Rivets]

The pulse line is the one going from the engine block to the fuel pump.

 

[Fish]

Please post the model and spec numbers off of the engine.

 

[greynold99]

Please post the model and spec numbers off of the engine.

Sorry for delay in getting back to this post but I wanted to try replacing the cheapo fuel line clamps Cub uses with small stainless screw-clamps... and, I thought I was onto something as the engine on starting up, sounded better to me than usual - although it's consistently started up good. But an hour later and I was having to disengage the mower and half-choke it to keep the engine running; although once I would start downhill or on the flats I could take off the choke and start the mower deck up again. I didn't replace all the clamps - namely the one underneath the fuel tank but only the 4-after the fuel-pump to pulse line to carburetor on the other side of the engine where it goes through as steel tubing.

I did have a question about the fuel tank and the fuel line connection... With fuel-filler cap off and looking down into the fuel tank, it looks like there is something more than just a hole-in-the-tank where the fuel line connects. Can someone comment on how those tanks are constructed and what, if anything could be clogging the outlet port? I'm going back to thinking about why the issue occurs mostly under-load while going up hill with this question.

Anyway, the full engine description is: Kohler Command 12.5 HP OHV, Model CH12.5S, S/N 2507317414, Spec No 1920, Disp(cc) 308
Family SKH398U262RA

Finally, I noticed there's another recent post on this type of issue with these older Cubs w/Kohler engines.
Thanks,
Greynold99

 

[knack]

My Cub is still acting up. Howeverif i pull the air filter and cruise the yard with the hood up i can spray some fuel in the carb and she pulls right back up to normal RPMs. I notice the fuel filter is not staying full when it acts up as well. Pulled fuel pump, all looks good. Replaced rubber fuel line and clamps but only between pump and carb left steel line between pump / carb. If i loosen fuel cap there is no improvement. Still think something between tank and carb. Only need to squeeze a few more cuts this year and plan on buying new this fall!!!

 

[DaveTN]

If you're riding on that mower w/ the air breather off and squirting carburetor cleaner in it and it'll pick up and run, you've definitely got a fuel starvation problem! Sounds like some small piece of trash getting over the inlet above the float needle and starving it for fuel. Or something causing the fuel flow to weaken or stop....perhaps some small obstruction in the fuel line intermittently starving the engine for fuel? If the filter is not getting gas the trouble would have to be above it going to the tank and including the tank. Could be dead insects in the tank as several mechanics on here have found as well! I found a clear piece of plastic, a remnant once on a plastic carburetor causing the metering valve to become clogged and thus starve the engine and it would die. Let it sit for 5 minutes or so and it would start back up and do the same thing. I finally ran a wire through and broke it loose. Hard to say just where the foreign matter might be lurking. I've never had much trouble out of clamps causing fuel starvation, altho they may. In a pinch I'll use wire wrapped around the hose a couple of times and twisted together.

 

[packardv8]

Yes, my 2135 with 600 hours exhibited the same problems. My first diagnosis was coil, so I replaced that. If I ever go in there again, the shroud will get cut in half with an air tool.

Finally, I did find a small piece of trash in the needle. I replaced the small fuel filter with a large, clear automotive version so it's easily visible if fuel is making it to the carb.

jack vines