Kohler Courage 18 driving me nuts

[WillG]

Worked on a Kohler Courage 18 recently on a Troy Bilt rider, oil change, resealed valve cover and rebuilt carb. Something went wrong with the carb rebuild so I replaced carb for her at no cost. Seemed to be okay. She just let me know that it's acting up on her again. Ran fine for a while then started surging badly. Definitely seems to be lean. Any suggestions? I have on order a new heat deflector kit which I'm suspicious of as being the issue. I'm not too well versed in the Courage so I'm working blindly.

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[redline4]

Didn't the Courage have the plastic cams that occasionally ate a lobe? Is it possibly a valvetrain issue?

 

[Matt Ellerbee]

I have the 19, I believe, on my cub cadet mower. Removed the backfire nipple and cleaned carb good. Ran well for awhile. Then started surging at idle rpm. I have removed the smaller black plastic piece in your picture, maybe that was the cause of my problems? It is long gone now. And only surges at idle, full power she runs fine. I live with it.

I realize this was no help. Lol.

 

[timg]

Just a suggestion Will. I've had the same issues on the courages and commands. Surging, intermittent backfiring, and low power complaints. They updated the coil packs as they have a timing module internally that goes bad. It's called a smart ignition, NOT so much. Engine model and serial number required for your dealer to check. Hope this helps you out.

 

[WillG]

She's also complaining of backfire/afterfire on shutdown. I know that the solenoid is working properly. I'm going to suggest to her that she idles it for a minute before shutdown. I really want to get to the bottom of this.

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[WillG]

Tim thanks for the suggestion I'll get the model/spec number and serial number from her and have a dealer check.

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[Larry B]

Sounds like a carb issue Running lean. That can cause backfire issues also. What brand carb is it? OEM or chicom? What does the spark plug look like? You say surging badly. When it surges does the the throttle linkages move in time with the surging?

 

[WillG]

Larry, OEM carb per model/spec number. I'm going to get out to her next week to have a look at it at her house.

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[WillG]

Talked with @Onan18 and he's seen plenty of the heat deflector/intakes cracked. Seems like I'm on the right track with my suspicion.

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[Larry B]

With it running you can spray nonflammable brake clean around the intake to check for leaks. If it is leaking the engine will stumble.

 

[WillG]

That's the plan

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[Nutball]

The wood splitter I use with a Honda engine will backfire sometimes like a second after it stops if we have run it for many hours. I think the muffler gets too hot. A neighbor's mower would do it too after shutdown.

 

[WillG]

Finally found the issue
Heat deflector between carb and head is cracked. Have a new one ready to go. Also did some digging and found that there's an update/repair kit for the shutdown solenoid with heat shield for the carb bowl and solenoid. Have that on order.

Thanks to @backhoelover thread a while ago for the bulletin on the solenoid.

Interesting video on the solenoid repair:

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