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have a kawasaki fr691v-bs29 that smokes light gray/blue smoke looks like a smokestack while running. did compression test each cylinder was 130 psi. did leak down on both cylinders had air coming out muffler. so do i have bad rings and bad valve on discharge side. was thinking value guides maybe but not sure to how to check them. any suggestion would be great help
thanks AC

Were all the valves closed when you did the leak down? All must be closed (TDC).

Continual smoking is piston rings/bore slash sealing.

Hello ACF,

How many hours are on this engine? Any maintenance history?

Having 130 PSI compression does not support failed rings, but they can stick the oil control rings. Change the oil and add a 1/2 cup of Marvel Mystery oil in with the new oil and that will unstick the oil control rings after a few hours of running.

As for your leak down test, it is best to remove the valve covers and verify both rockers on each head are loose fitted, and the piston is held at top dead center in the cylinder. Better yet, back the rockers off and remove the pushrods to get the best results to verify if there is actually a leak down past the valves. A little air from the dip stick tube is normal, but a lot is not good.

If you happen do the heads, lap in the valves to ensure proper sealing and replace the valve seals.

engine has 135 hours, removed valve covers to verify tdc, got nothing from dip stick just muffler

slomo said:

Were all the valves closed when you did the leak down? All must be closed (TDC).

Continual smoking is piston rings/bore slash sealing.

Click to expand...

135 hours and was tdc had valve covers removed watched springs

Check valve lash per your engine manual.

Pull the rubber tube for the air filter off from the intake pipe (before the carburetor). If you live in the south, the engine is possibly dirt ingested due to inadequate air filter maintenance. Sorry to say but I see a lot of it. Valve guides are not the issue.

Auto Doc's said:

Hello ACF,

How many hours are on this engine? Any maintenance history?

Having 130 PSI compression does not support failed rings, but they can stick the oil control rings. Change the oil and add a 1/2 cup of Marvel Mystery oil in with the new oil and that will unstick the oil control rings after a few hours of running.

As for your leak down test, it is best to remove the valve covers and verify both rockers on each head are loose fitted, and the piston is held at top dead center in the cylinder. Better yet, back the rockers off and remove the pushrods to get the best results to verify if there is actually a leak down past the valves. A little air from the dip stick tube is normal, but a lot is not good.

If you happen do the heads, lap in the valves to ensure proper sealing and replace the valve seals.

Click to expand...

changed oil and added marvel mystery oil ran for over 2 hours was worried at beginning but after over 2 hours no smoke, do get a little puff when throttle increased, now would you adjust the valves

Hello ACF,

A little puff of smoke at throttle up is not a bad thing. It will likely clear up with more use. Using Marvel Mystery oil is a very slow way to break down sticky carbon on the piston rings and ring grooves. Your power will likely improve slightly as well.

Yes, adjust the valves would be the next thing to do. Adjust when cold. Pull the plugs so you can rotate the engine by hand using the top flywheel screen. Do one valve at a time while the adjacent one is fully open on the same cylinder.

Here is a video:
https://www.bing.com/videos/rivervi...8CD77450E24618145DD88CD77450E246&&FORM=VRDGAR

Also, check out a site called Teryl fixes all, he knows his stuff. He does dress funny and has some "creative skits" in most of his videos, but he knows his stuff when it comes to small engine equipment.

As for the Marvel oil, it does more good than harm to leave it is there for a while, then do a regular oil change before you park it for winter, or before you start it in the spring.

Air cooled engines are bad about carbon sticky rings, especially if the fuel sits too long.