Kohler fuel issue

LawnWizard

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Working on a Kubota ZTR with a Kohler CV682 3024. Engine starts right up and runs good for about 5-10 minutes. Then will shudder and die. Let sit for about 10 minutes, same exact thing.
Good compression on both cyls. Plugs weren't bad but I changed anyway (they had 100 hours on them). I verified that it is a fuel issue. Right after it stalled, I pulled the fuel line off after the pump. No fuel when cranking so I replaced the fuel pump. (Already changed the fuel filter). Same result, 5-10 mins then stall. I put in fresh gas, checked the tank for crude, and verified the lines are not plugged. Now with new filter and pump, there is plenty of flow coming out of the pump.
So, question: is there anything other the carb that would cause the above situation? If it is the carb, why does it run so well until it doesn't? Could it be the fuel vent? Thanks for any assistance.
 

Auto Doc's

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If this model has a fuel vapor check valve (usually hidden) in the top of the fuel tank, that is a likely suspect.

Like Scrubcadet10 said, try it with the fuel cap loose and see if it keeps running like it should. Many of the newer machines no longer have an atmosphere vented fuel cap. Air must get in the tank as fuel is being used. If not, cavitation (vacuum) occurs, and the engine gets starved for fuel.
 

LawnWizard

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Joined
Nov 17, 2021
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If this model has a fuel vapor check valve (usually hidden) in the top of the fuel tank, that is a likely suspect.

Like Scrubcadet10 said, try it with the fuel cap loose and see if it keeps running like it should. Many of the newer machines no longer have an atmosphere vented fuel cap. Air must get in the tank as fuel is being used. If not, cavitation (vacuum) occurs, and the engine gets starved for fuel.
It does have a vent that is attached to the ROPS bar. I can't recall ever have a bad carb that worked perfectly for 10 minutes at a time before. Hence my question. Thanks for the reply. Will check tomorrow and report back.
 
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