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Preventing stuck valves....

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Ezflyr

Well-Known Member
Joined
Jan 12, 2018
Messages
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Location
Lawrence Municipal (KLWM)
Hi All,

My C85 powered cub recently had a stuck exhaust valve in cylinder #4. My mechanic and I dropped the valve, cleaned the valve guide, and reassembled everything with great success. Normal operation was restored in under two hours of labor.

Now, going forward, what can be done to minimize the occurrence of stuck valves? At a minimum, frequent oil changes seem to be a good idea. Previously, I was performing an oil change at 25 hours, but I may shave a bit off of that now, and use 20 hours as a maximum. I'm also going to start using Camgaurd oil additive at each oil change.

My Cub has a Stromberg NA-S3 carburetor with the mixture control safety-wired full rich. I noticed that the inside of the cylinders and the plugs on my Cub are quite dirty/sooty. I fly only at a seal level airport, and I'm wondering if a mixture control in the cockpit might be a good idea to help the engine run a bit cleaner. Would this have a significant impact on preventing future stuck valves?

Thanks,

John
 

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