Kohler ECV749 (EFI 29HP) Surging at mid to high throttle when idling

[Aikaru]

I have had a surging issue on my motor for quite a long time now (About three years) and never paid much attention to it. When warm, the engine surges at mid to full throttle when idling but does NOT surge when at the lowest throttle position. However, when the PTO switch is engaged at full throttle, the surging immediately goes away and the engine smooths out.

When the engine is surging at idle, you can visually watch the governor constantly move with the sound of the surging as if it is what is making the engine surge.

I have performed a complete electrical system reboot which did nothing. I have done an oil change, a spark plug change, a fuel filter change, and an air filter change and the surging has not gone away.

I have also checked for any vacuum leaks and there are none.

Could the ECV system be out of wack?

Thank you.

 

[ARN Greencare]

You mean it surges at mid to full throttle under no load?

 

[Aikaru]

You mean it surges at mid to full throttle under no load?

correct

 

[ILENGINE]

Doing a TPS relearn may not be a bad idea to see if that improves the idle. It is very possible that the TPS is getting worn sending erratic signals to the ECU. May require a TPS replacement in the future.

 

[Aikaru]

Doing a TPS relearn may not be a bad idea to see if that improves the idle. It is very possible that the TPS is getting worn sending erratic signals to the ECU. May require a TPS replacement in the future.

Okay...what equipment do I need to perform a TPS relearn?

 

[ILENGINE]

You can download the service manual for your engine on the kohlerengines website under service heading at the top and then click on manuals and input your model number scroll down and click on the manual

 

[ARN Greencare]

Some of these things had governor spring issues causing what you're describing. It won't harm anything, and there's nothing wrong with the fuel management system. Some have different holes to position governor spring to make it less aggressive. Of course you'll need to reset the engine speed.

 

[Aikaru]

Some of these things had governor spring issues causing what you're describing. It won't harm anything, and there's nothing wrong with the fuel management system. Some have different holes to position governor spring to make it less aggressive. Of course you'll need to reset the engine speed.

Just fixed the surging issue lol. ILENGINE was right, the TPS just needed to be reset.

I know when I took it to a "professional" like two years ago, they adjusted the idle speed without resetting anything so that could've messed up the entire ECV system.

I took a black wire and jumped the molex connector for the computer diagnostics on the engine, which evidently reset the entire computer system to factory default.

It surged for a few minutes after the reset but soon smoothed out at idle at all throttle speeds (Since it had to relearn)

Every time I start up the engine it just gets smoother and smoother.

Thank you guys for the assistance! Happy Holidays!