hello
i have a 73 inch wing hanger 9 cap with a mds 148 with a pitts muffler on it. it has all new fuel lines. i can prime the engine over and fuel gets to the carb. it will start after about 2 turns and run for a few seconds but then quits. it seems as though it runs out of fuel, when i open the carb the fuel runs back to the tank. the tank is a little below the carb but their is no other place to mount the tank. it seems to me that when started it should continue to run because the tank should be pressurized at this time. i think their was a prob with the older mds carbs but im not sure. the engine is mounted sideways as per instructions, and their doesnt appear to be any leaks. turning the engine downwards doesnt look like it would change the position of the carb any.
any help would be appreciated
thx
robert

Honestly, It sounds like you might have a fuel tank/line problem. I have had similiar problems. Usually a cut in the line or a split seam. If it's not leaking the split may be on top. (or a carb with problems)

also changed engine, mds 78, just to see if it would run, and it ran no problems????
so i think it mite be a carb prob?

You also might want to check for "garbage" in your carb. I found out a small piece of junk can really screw up the way an engine runs. That is my experience.

Sometimes the pitts muffler won't allow the tank to pressurize enoigh for good fuel flow. Try blocking off ONE of the exhaust pipes with a rubber cap temporairly to see if that fixes your problem. If it does, you'll have to make it permanent.

Try richening the LOW speed needle a full turn ccw and see if there's improvement. If yes, continue till the desired result is obtained.

I would agree with wildcrashwilly. The pitts mufflers sometimes don't create enough back pressure. Plugging one pipe should fix the problem if the lack of back pressure is the problem.

Your glow plug may not be the right heat range for what you have it in. Nitro content. altitude, humidty, you make W.A.G. bet it is the plug.

Hi, open the main needle four complete turns, idle screw (needle) two and one half turns, Enya no3 plug ( or better a Taylor with idle bar) and, providing there is no crap in the carb it will run.
Chris
P.S. Damn good engines!

Rtonytiger,

Just curious, have you got your engine to run yet? If so, what did it take to fix it?