weirdjim
Ejection Handle Pulled
- Joined
- Jul 8, 2008
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- Grass Valley, CA (KGOO)
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weirdjim
About 5 months ago, a fellow's engine went to idle about ten minutes into climbout and he stuffed it (undinged) onto the freeway. Engine stayed at idle (about 800 rpm) until he shut it off after landing.
Fired it up the next day on the ground and it ran at normal power for about two minutes and then went to idle. No combo of mixture, carb heat, or throttle had any bearing on the problem. Did it a few hours later, same thing. Did it the next morning, same thing.
Pulled the fuel line off at the carburetor and let it pour (steady stream) into a jug and convinced ourselves that it wasn't going to take over a quart a minute for an hour to keep the airplane in the air. Engine controls were tight and secure.
Pulled the carburetor (metal floats changed and overhauled about five years ago) and the only anomaly we could find was about a half-thimblefull of dirty water at the bottom of the bowl. Floats were free. Passageways appeared unclogged.
Put it all back together and ran it up and it went for a good half hour with no apparent problems.
Now we all know that unfixed problems will most probably recur. I'd rather not have them recur with this fellow on departure again, especially as it will be my signature in the logbook for the annual.
One thought I had was to take the carb down to the local ... um ... "aviation" carburetor fixit shop and have them flow test it for an hour or so. If there IS a clog in a passageway that isn't optically visible, this might find it, or it might have been a clog that we loosened and blew out the exhaust when we disassembled the carb and then ran the engine after reinstallation.
Thoughts?
Jim
Fired it up the next day on the ground and it ran at normal power for about two minutes and then went to idle. No combo of mixture, carb heat, or throttle had any bearing on the problem. Did it a few hours later, same thing. Did it the next morning, same thing.
Pulled the fuel line off at the carburetor and let it pour (steady stream) into a jug and convinced ourselves that it wasn't going to take over a quart a minute for an hour to keep the airplane in the air. Engine controls were tight and secure.
Pulled the carburetor (metal floats changed and overhauled about five years ago) and the only anomaly we could find was about a half-thimblefull of dirty water at the bottom of the bowl. Floats were free. Passageways appeared unclogged.
Put it all back together and ran it up and it went for a good half hour with no apparent problems.
Now we all know that unfixed problems will most probably recur. I'd rather not have them recur with this fellow on departure again, especially as it will be my signature in the logbook for the annual.
One thought I had was to take the carb down to the local ... um ... "aviation" carburetor fixit shop and have them flow test it for an hour or so. If there IS a clog in a passageway that isn't optically visible, this might find it, or it might have been a clog that we loosened and blew out the exhaust when we disassembled the carb and then ran the engine after reinstallation.
Thoughts?
Jim