Oil from crankcase in carb 425


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Oil from crankcase in carb 425

scott Gentlemen; I noticed my plugs foul frequently on my 425 V2 Kawasaki engine. I think I had found the source. Seems that oil is entering the carb via the breather tube. I am sure it is doing what it is intended to do but it seems there is to much oil. I checked the compression of the motor and it seems to hold. Any other ideas what may cause this???? A few summers ago I did replace the cam gear/shaft tappets and water pump
ross What plugs are you running in your engine? Any water cooled Kawasaki should be running a pretty hot spark plug. I have the John Deere part number it is AM122402. These seem to help a lot.
scott I will have to check. The current plugs that are installed are the standard NKG that come from the parts list. Did you asked for a hotter plug from the standard spec plug????
ross I always put the hotter plug in the liquid cooled Kawasaki.
dan I've got a jd 445 that is behaving quite similar. I can actually watch the oil enter the carb (throttle body) via the breather tube. I also checked compression which was also ok. Could this be potentially caused by the breather valve? This is creating a quite smoky machine!
scott I figured this out last fall. In my case, the reed valve which acts as a pnematic check valve was stuck on its backing plate allowing oil blow back into the carb. To check this bugger is not easy. The motor needs pulled and the flywheel needs pulled also for the $1.24 reed valve. The only mention of this in the deere manual is the thickness of the valve. Total time for me to do the job 3.5 hours. Also before doing this work you may want to check rocker arm cylinder valve clearence. good luck
Dan Thank you much for the info Scott! We were planning to pull the motor and attack this over the weekend. It's good to hear that our theory could actually be correct!?
scott Hopefully you will receive this prior to yanking the motor. One way to determine if the PVC valve is stuck open is with the engine running and warm at an idle pull the dip stick to feel a slight vacuam with your finger over the tube. If a vacuam is felt or a negative pressure the valve is good if it is stuck a positive or blow out is felt. When the piston goes up I believe the vacuam is created. when down the valve is suppose to close, if it does not it blows the oil all over the crankcase including in to the pvc area then into the carb fouling your plugs. As a note I also switched to the plugs deere uses in the Gator Kawasaki per the deere dealer. They burn hotter preventing fouling. If you have any questions call me at 724-452-5212

scott Some Other items, You will need a flywheel puller to remove the flywheel to access the PVC valve plate. I had actually found my drift key broken once I removed my flywheel. Try to be carefull when removing the pvc cover to keep the gasket in tacked if you do find the PVC metal reed stuck agaisnt the back plate a few swipes of emory cloth will clean it up and you can reassemble with out waiting for a new gasket from deere. You may also check your valve/rocker arm clearence when the engine is warm. I believe it should be .010" on all valves. I understand this can also cause blow back. The Kawasaki is a pretty little motor. The only other problem I had in 1400hours is the plastic cam gear had shifted a few degrees which was a known issue in the early engines deere had speced that engine. Good Luck!!
dan We ended up pulling the motor and cleaning up the PVC valve, which seemed to be operating correctly. After re-installing the motor we adjusted the valves to .010 as specified in the service manual. This had no improvement on the situation. I checked the crankcase vaccuum using your suggested dip stick test.... There was extreme positive pressure or blow out! It eventually began blowing oil out the dip stick tube. Not sure where to go from here, I think we're going to pull the motor again and tear it down?. I'm guessing valve seals, piston and rings, or worse (cracked or warped head). Not sure if the cam gear could be a possibility or not?
scott Bummer!it wasn't the cheap PVC valve. I think if it was the cam gear shifting on the shaft it would run rough as mine had. It only shifted a few degrees.You did a compression test? If I rememeber it calls for 170psi @ each cylinder. The deere dealer had mentioned using the correct oil grade. Reply back to me with what you find.
Thanks

Dan Well... we tore the engine down and found several issues, leading us to believe that the hour meter may not be as accurate as what it reads. Valve seals had been leaking, bent pushrod, ring grooves in a piston had excessive slop, one cylinder was a bit oval shaped, and we also discovered several other leaks that were not as obvious before tear down. I'm a bit frustrated with the purchase of this machine and have requested that the seller (a John Deere Dealer) assist with the repair. We see how that goes….


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