Is the height of the fuel tank outlets in relation to the carby inlet critical? I'm having problems getting my 35 size started. To prime it, I have to have the throttle fully open, cover the carb, and spin the prop heaps to get fuel through. Glow plug and fuel tank both new.

The relationship of the fuel tank to the carb is very important. The horizontal centerline of the tank should be no higher than around 3/8" above the needlevalve (spraybar). However priming the way you are should flood the carb. Check to make sure you have not inadvertantly switched the pressure line with the feedline, i.e. the feedline is the one from the carb is the one that goes to the clunk in the tank. An easy mistake that happens all the time.

John

Ok, here's more info. Its an Enya 35, the only way it starts is to squirt fuel into the carb. It then starts no problems. However, the revs slowly fluctuate on a steady throttle. Question, I've adjusted the high rpm mixture screw. What is the adjuster screw next to this main mixture screw, and what is the other adjuster screw on the top face of the carby? Low and mid range? Which is which?

If you can't prime the engine by setting for full throttle and covering the inlet with your finger, you have an air leak somewhere.

An airleak can also cause changing RPM at full throttle, as the vibration of the running engine causes the leak to allow more or less air in, changing the mixture setting.

I'm not familiar with the carb in question. However, in general, if there is a screw (or two) sticking upwards from the top of the carb, it's there to either limit the carb travel (called the throttle stop screw) or to hold the carb barrel in the carb.

The low speed mixture will be one of two things. It might be a small screw opposite the needle valve (or spraybar on RNV engines), This is the low speed needle, and the carb is a "two needle" carb. (there are actually a couple of different types of two needle carbs, but that's more detail than we need).

Or, it will be a small screw parellel to the needle (or spray bar) that opens and closes a small hole in the front of the carb. That second type is called an "air bleed" carb, and the screw is the airbleed screw.

Which model Enya is it? If it's the early cast iron piston with the removeable front end then check to see if the top right hand screw is tight. This leads directly into the crankcase and will stop you from priming if it's leaking. From memory these carbs are held in by short screws either side of the carb so check them for leaks too. I think there's also a gasket where the carb seats.

If it's the cast iron piston then I hope you're using lots of castor in the fuel