the engine is a beauty. has ran well for over a year, moved it to the new plane ( Harmon Rocket 111) Had to turn it 100 degrees on its side , as per intructions. now the problem i have is the the needle setting of 2.5 turns is ok . and can lean it out. but i can turn it anti clock wise and it still runs. tho very rich. i can undo the needle till it nearly comes out of the housing. What have i done wrong???????????????????????????[:@]

Doesn't sound like anything's wrong. 2-1/2 turns out from closed would normally be a very rich setting. To tune the engine, you'd turn the needle clockwise to lean it towards peak. Turning the other way will richen...but many times, the inlet of the engine prevents going rich beyond a point. If the needle falls out, we'd expect the engine to lean and die.

Thanks for that Bax. but yet why does the engine needle work perfectly when the engine is mounted upright, and yet when it is mounted inverted why does it work differently? does that make any sense to you
joe

If the needle settings are very different when you mount the engine differently, then you have to look at the fuel system. What's the tank position? How are the tubes mounted in the tank? Are the tubes OK? and so on. You should not see radical changes in needle settings.

is there a rule of thumb with relation to the height of the fuel tank and the carb and needle? sorry if this sounds stupid.
joe