OS 50 (non-hyper) has the hiccups

[tracerbob]

I ran out of the usual fuel I use, 15% cool power, Which the LHS does not carry, so I had to try 15% mach 7. I gassed up, lifted off and settled into a hover and the engine started missing like a 4 stroke with the timing off. Richend it up a bit, no change. Could it be sucking air? I replaced the stock clunk lines with the good stuff awhile ago but wouldn't this show up gradually? Is it the fuel?

[DavidH]

Where did you get the Mach 7 and how old was it? Sounds like the Mach 7 is contaminated with water due to it being old.
Mach 7 15% and Cool Power 15% are virtually the same. Different color is difference. They are made in the same plant.
Mach 7 is fuel that can be ordered directly from Morgan by customers. I am not sure they are still selling it. I believe they were going to quit making it and selling it directly in 2006. Morgan use to keep a website for the Mach7 and run ads in magazines. The website has been gone for a while and no ads in mags for long time.

David

[tracerbob]

David, you make a good point. Our club buys it direct from Morgan fuels since we are about 3 hours from the factory. I never thought about the fuel being contaminated. I have some Byrons fuel (which I hate as the smoke is so intense it burns my eyes.) Perhaps I should run a tank of that through to see if in fact it is contaminated fuel before I take everything apart. Thanks!