Zippi

My Feedback: (10)

I only have about a dozen flights with my new OS 120AX and last Saturday on the first flight of the day I had trouble. I fired the engine up that morning and it sounded like it was slow to come up to full throttle. I'd been running the low end and high end needles on the rich side since the engine is new. I thought it might be the weather since it has been close to 100 degrees and that day it was in the low 80's with low humidity. About 2 min into the flight the engine started loosening power so I landed and the engine died. I pulled the cowl off and the engine head was dark colored and all the head bolts were loose. I guess sucking air around the head made the engine run lean and get hot and start loosening power and die. I added blue loctite and retightened the bolts and changed the plug and fired the engine up and it seemed ok. I'm wondering where I stand with the warranty? Should I go ahead and fly or do I need to send the engine in to be checked out under the warranty?

Bax

My Feedback: (11)

If the engine's running well, we'd not be too concerned. Please realize that head bolts usually loosen if the engine's had an overheat. Aluminum will expand more than the steel, so the bolts will get a bit stretched. When the engine cools down, the steel bolts won't go back to their original size, and will be a bit loose. Further running will cause them to loosen some more. When you tighten the bolts, make sure the engine is at room temperature. If you tighten the bolts when the engine's warm, they'll just loosen again.

Zippi

My Feedback: (10)

Thanks for the info.