OS 91fx fix
05-12-2005, 07:05 AM
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OS 91fx fix
Just wanted to share my fix for a solution to cure 91fx fuel bubble problem. I was getting bubbles in the fuel line between the remote NV and carb. New O ring only helped for awhile. My fix involves removing the ratchet spring on remote needle and using a piece of large silicon fuel tubing, cut about 1/2" long. Remove needle valve and force tubing down over the needle body, then replace needle assuring it goes inside tubing. Ratchet spring no longer used. Worked for me.
Good luck, red
Good luck, red
05-28-2005, 09:41 PM
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RE: OS 91fx fix
This has been beat to death!! PLus, ive tried just about all the fixes, and its not worth it anymore!! Had 2 .91 FX's, and will never own another!!
05-29-2005, 09:38 AM
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RE: OS 91fx fix
The heat transfer from the engine is what cause the bubbles in the stock needle valve.If the stock needle is cut off the engine it works fine.You can let it dangle or mount it to the firewall.
05-29-2005, 09:47 AM
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RE: OS 91fx fix
Kelly:
The ones with the air leaks were not corrected by removing them from the engine. Some were heat related though, those few were corrected with your method.
The cure that worked for ALL included tossing the junk OS needle. And adding a Perry Pump.
Bill.
The ones with the air leaks were not corrected by removing them from the engine. Some were heat related though, those few were corrected with your method.
The cure that worked for ALL included tossing the junk OS needle. And adding a Perry Pump.
Bill.
05-29-2005, 07:46 PM
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RE: OS 91fx fix
I don't seems to have this problem with the new OS91FX although I'm still running the first gallon and I have gotten some good flight without fuel cutting or deadstick which I believe more related to my tuning. Running without cowl, I did not see any bubble. I believe they replace them with new needle valve setup ie a separate plate to mount the needle valve and the needle housing is some kind of composite/plastic? No more heating up.
05-29-2005, 08:02 PM
#8
05-29-2005, 08:39 PM
#9
RE: OS 91fx fix
I have always watched the 91FX problem threads. They seemed to parallel the problems I experienced with several 50SXs. Very small air bubbles in the remote needle to carb fuel tubing. I think it too was heat or vibration related. Funny OS claimed there was no problem, but replaced both.
