I have a tt.42 gp on a morris knife edge. I have a lot of problems keeping it running smoothly, I have the fuel tank mounted outside the wing opposite the engine at the same level as the carb but it seems as if the fuel is not flowing properly. I have adjusted the high/low adjustments screws, and moved the tank to different positions, yet I keep having a problem keeping it running smoothly, if it decides to stay running at all. maybe if someone else has this engine setup as a side mounted engine on a plane like this you could suggest something.??

Unfortunately the TT factory never tightens screws and bolts much beyond finger tight. This results in air leaks, which results in erratic running.

Tighten the head, backplate, carb body, needle valve body, and everything else you can find on that engine. This will stop the air leaks and let the engine run normally. The TT 42GP is a great engine! I've got three of them that I'm using in combat and fun fly planes. With a mousse can pipe, they run even better.

I'd also suggest starting with an OS #8 plug. Once you get the engine dialed in, then try experimenting with other plugs.

...what Dave said above!

Also, with a MAC's one-piece muffler and a MA 11X5, the GP-42 will pull up to a 4 lb. "all-up weight" plane around with authority.

Greater than 4 lbs., you will wish you had more motor!

The engine is not a new engine, I had it on a different plane for two years with a lot of flight time on it. However since I mounted it on this plane I have had no success at keeping it running reliably. I'm thinking it could be the fule tank, I meay replace it as a first step.???

I ran into the exact (almost) same problem as you did. I purchased a GP 42 for use on my something extra about 2 years ago, then due to other happenings, It took me like 2 years to finish the plane. In that time I had "Broken In" my thundertiger...then it sat....for like a year. Finaly finished my SE and slapped the 42 back on.....ran like crap....no matter what I did...wasn't consistant, would periodically die.....ect.

I finaly got fed up with it and tore the whole thing apart, every nut, screw and bolt. Cleaned everything really good and put it all back together again...

It ran like a Champ!!, still not enough engine for the SE, but a whole lot better than it had been before.

I think what happened was that I didn't clean all the fuel out before I put it away after not running it for a while....there were some very small peices of something (looked like evaporated/coagulated fuel) in the carb....might be a good place to start....pull off the carb, take it apart and clean it.

Give it a shot...