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timing a 220 gpu

Ok here ya go
The timing should be 25 deg. advanced. unless you have real high compression pistions.

Find #1 cylinder, with mag out ( so engine cannot fire, or take all top plugs out) pull prop. arround with your finger in plug hole till compression stroke, when piston is at TDC stop. ( might use a small screwdriver on piston) Now if your flywheel is degreed, back prop up to the 25 mark. locate the red 1/2 tooth on mag gear by looking in the small hole in side of mag, and set mag in engine. The 1/2 tooth should be in middle of the inspection hole, with crank at 25 deg before top dead center.
If you dont have a degreed flywheel, you can use a protractor.
hope this helps.
That's one of the easiet to understand descriptions of that procedure I ever read. I enjoyed it, and I run a car motor :lol: ! Thanks.

Easier to understand than the article in Airboat World a while back. I read that several times and still didn't make sense. And it had pictures! :shock:
Aircraft are simple engines, mostly designed 50 years ago.....high torque, low rpm engines, so planes dont fall out of the sky, cause gravety allways works....
Davie - but most people cannot make it simple and most that do make it impossible to understand.

You should talk to Lycoming about helping write their manuals.

And if you like and understand computers, then you could be a millionare telling others how to do things.