Upsidedown Engine
 

Help guys! I just finished my U Can Do and took it out for the maiden flight today. This is my first go at an inverted engine. It is a Supertigre 90 that has had about 40 ounces of 15% Coolpower ran thru it. I first tried it with a Perry Pump and it was fine on the stand but when on the plane it just kept loading up and flooding the plug. I bypassed the pump and tried it again a little better but it would go dead on the taxi out. Then I turned the plane upside down and got the high and low needles set and managed to get it airborne, made 1 trim pass and it went dead again. I just gave up for the day. No need to mess up a new bird over something like this. Any info appreciated. I am going to take the carb off and clean it good it may have some fiberglass dust in it from the cowl fitting?

Upsidedown Engine
 

Doesn't hurt to clean out the carb, but you should really tweak out the engine the way it will be installed in the plane... inverted. Also try a hot plug like an OS#8 or Type F.

Upsidedown Engine
 

Make sure the tank is not to high. Centre line of tank should be about 1/4 in below carb spraybar. sounds like it might be loading up.

Upsidedown Engine
 

I think that's a ringed engine? In that case it's no where near run in yet and 15% nitro might be a bit much for it anyway.

But it's definitely loading up at idle. Inverted engines are much more critical to idle mixture than what you can get away with normally. Use the pinch test to set the idle and aim for only a very slight rise in revs. You could try an idle bar plug too. Flypaper had good advice...sometimes the obvious gets overlooked.

Upsidedown Engine
 

Cleaned out the carb last night and installed a OS F plug this afternoon. Ran out of daylight But I did check the tank level. It seems to be a little above the carb but I thought the pump would help regulate that. I am going to try it again tommorow. Thanks for the imput so far.