Kohler Genset Black Smoke

[Kameroo]

My 6.5 kw Kohler genset ran great last season. This year, it started right up, but when loaded seemed to run a little slow and not produce 110v--it was more like 100v. I shut it down and observed black soot by the exhaust.

Sound like a carb issue? I got some Sea Foam to run through it with an external gas container, but wanted to check with the experts for other ideas first...

 

[kpetry]

You didn't mention black smoke this morning! Typical patient...doesn't give the whole story when you ask about symptoms.......:grin:

Make sure your choke is shutting off after the gennie starts. Take off the air cleaner and observe the choke butterfly. It should be more or less closed when it starts cold, and then open as the gennie warms up. Not sure if your choke is mechanical or electric, but if it's electric be sure all connections are clean. That's the first thing I'd check. If you have black soot, It's running rich for sure. Plugged filters or dirt in one of the jets like we talked about this morning will make it go lean - no soot.

The next most likely thing is that the carb float is sticking. This can also easily occur during layup. You'll get the same symptoms - rich. Try rapping on the carb float bowl with a wrench to break loose a stuck float, and see if it improves. If not, you'll need to remove the carb to work it over more thoroughly with some carb cleaner.

Should be a relatively easy fix you can do yourself.

 

[370Dancer]

and if it ran rough without getting to voltage, try changing the plugs (unless you just did)

 

[Kameroo]

Thanks guys. Kurt, I didn't see all the soot around the exhaust until today. I figured that would be a dead giveaway that maybe it was rich, so the choke sounds like a good place to start. I'll try all the above and report back. I also picked up a can of "Sea Foam" carb cleaner that I can mix into a gal. can of gas to run a separate line straight to the genset for troubleshooting.

 

[Kameroo]

PS: Anybody know of a good place to find those plugs? I'll check the book on the boat tomorrow to get the numbers. Last time I tried around time, I came up dry.

 

[Moose]

Sounds like plugs to me!

 

[MExcelsior]

Was this the first time that it was started this year? It could be that you are burning fogging fluid. I usually replace my plugs after the first start every spring because of this.

 

[Kameroo]

Make sure your choke is shutting off after the gennie starts.

Kurt wins a beer! Something must have gotten bumped last time somebody worked on it, as there was a small wire connector under the choke that was blocking its movement. Bent it down slightly, and all was good.

I ran some carb cleaner through it just for fun and brought home the air filter so I can find a replacement. She purrs like a kitten, even under a good load.