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Hey guys, I have a Kawasaki FR651V that seems to be running rich after installing a new carb last fall. The plugs show carbon build up after only about 25 hours of run time.

Last weekend I adjusted the valve lash, did an oil change and replaced the plugs. I’m assuming that I need to adjust the air/fuel ratio but I’m finding mixed info on how to do this. Anyone have a good procedure to follow?


Thanks!

Tim

Looks like oil to me. Threads are covered in oil as well. Look in the thread valleys.

How much is the oil over filled? Dump out a few gallons and check oil on flat ground.

You know on a Kawi, you park the stick on top of the threads and check oil level. Don't screw it in then check the level.

That plug gasket looks compromised. See that area on the very top center of the plug? Like the gasket is deformed?

Not sure there is any air / fuel ration adjustment but I agree with Slomo assessment, be sure your air cleaner is clean also. Running rich will not give you blue smoke in my opinion, running rich will not run well at all and will be struggling to keep at idle too.

Today’s carburetors are not adjustable for fuel mixture (EPA regs). Possibly the wrong carburetor, i.e., aftermarket. Dirty carburetor or choke not adjusted properly.
Running rich will make the spark plugs appear to be sooty. The soot is unburned fuel.

That looks like oil. Carbon fouling will appear dry.

Thanks for all of the input guys. It was not overfilled with oil. Both plugs look like this. So, seems like an issue with rings or valve seals then?

I would say bad rings or head gasket. Does it smoke at all? It might be really faint and hard to see, so you could shine a flashlight next to the exhaust to see it better. Also check that your choke butterfly is open all the way

Bertrrr said:

Not sure there is any air / fuel ration adjustment but I agree with Slomo assessment, be sure your air cleaner is clean also. Running rich will not give you blue smoke in my opinion, running rich will not run well at all and will be struggling to keep at idle too.

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Blue smoke is burnt oil. Black smoke is rich excess fuel.

txmowman said:

Today’s carburetors are not adjustable for fuel mixture (EPA regs). Possibly the wrong carburetor, i.e., aftermarket. Dirty carburetor or choke not adjusted properly.
Running rich will make the spark plugs appear to be sooty. The soot is unburned fuel.

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For the most part I agree. Some you can install a different main jet size or a high altitude version of it.

twernicke said:

Thanks for all of the input guys. It was not overfilled with oil. Both plugs look like this. So, seems like an issue with rings or valve seals then?

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twernicke said:

Thanks for all of the input guys. It was not overfilled with oil. Both plugs look like this. So, seems like an issue with rings or valve seals then?

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So oil was perfectly on the FULL mark? Not one bit over full?

One side of the stick over the full mark and the other not over FULL?

Make sure, for testing, keep both sides of the oil dip stick below the FULL mark. Moral of this is keep her on the FULL mark, nothing more nothing less.

Do you run a bagger ?
Baggers emit very fine dust that can get sucked into the engine and wear the rings
I have done quite a few re-rings on Timecutters fitted with Kawasaki engines because the air filter is a bad design and easily leaks if overtightened .
The solution is to fit the FX filter and if the customer will not do that then a heavy dollop of rubber grease .