I am having trouble getting my Megatech .46 2-stroke adjusted and hope someone has some suggestions. The engine ran fine on the bench- it's now on a Great Planes P-51 mounted inverted with standard muffler. It's a brand new engine with about 4 tanks through it now. Mounted on the plane it runs ok with the glow starter on for the most part, but seems to run really rich on the low end and won't lean out. I just put in a brand new plug. I noticed fuel was dripping from the carb after it's shut off for the first few minutes. Won't transition smoothly but runs ok at full throttle even with the ignitor off. I can also see bubbles in the fuel line to the carb while it's running. With the inverted engine the carb is slightly below the tank level, but not much and looks like it's siphoning a bit. It doesn't seem to matter what I do, the mixture won't stay consistent and I'm having to change it at different throttle settings to keep it running smoothly. Unfortunately, inverted seems to be the only option recommended without going to the Pitts muffler. I have left off the cowl and fuel filler valve until after get it adjusted. The muffler has a pressure tap in front of the baffle and it seems like it may have too much tank pressure. Would it help to remove the baffle, or anyone have any other suggestions? Thanks-

I would try to reposition the tank to a slightly lower level, if possible

I have had the same problem with inverted 2/s engines. I think I am going to design a test stand for inverted mounting. This way, I can hopefully find the solution to this problem. I have a sig Kiwi nib and want to install my engine inverted like the plans show. Since this kit is now very hard to find, I want to make sure the engine will run reliably inverted before its first flight.

Jimmy

If you have the cowl off and the engine idling, pinch the fuel line. You should hear the engine speed up. If it does your idle needle is too rich. Screw it in (clockwise) about an 1/8 turn and try the pinch test again. Keep doing that until the engine doesn't speed up any more or just quits. Your very close to a good idle now. You may have to back it out 1/8 turn. When the engine idles good for a minute or two hit full throttle. The engine should accelerate immediately. If it quits instantly on acceleration your idle needle is too lean. An engine will run very good inverted. It just requires a good idle setting.

Do what Mettler says and get the idle setting perfect. Then things will work great. Don't worry about the siphoning or the muffler - those aren't your trouble.

To prevent hydrolock: before starting, turn the plane up on one wingtip so that the muffler is down and any fuel/oil will run out of the engine into the muffler. Flip the prop a few times to flush out the engine, then turn the plane nose up to let the gook run out the exhaust and drip on the ground.

Set the plane on it's wheels. Prime the engine (thumb over carb and flip a couple times) then hook up the glow and it SHOULD start right up if you back-flip the spinner - no starter required.

Hi!
If you have bubbles in the fuellines something is definitly wrong!!
No bubbles should be present!

Regards
JK