Hay guys I just bought an Avistar already built by someone else and have flown it several times having trouble getting it to run proper and opened up the front deck to add a little lingth to the feed lind and notice that the pressure tube inside the tank is turned upwards to the top of the tank. is this correct or is it suposed to be turned down? The motor runs well at high speed but will not idle proper.

Thanks, Miloh.

That pressure tube inside the tank should be turned up towards the top of the tank, but not touching. I've solved idle problems by SLIGHTLY adjusting low end screw. Turning it clockwise leans out and counter clockwise richens, same as high speed needle. Try leaning it out a bit first if the motor sounds like its"blubbering". Actually your thread would probably get real good advice in the engines forum. Good luck

yea I've been alover it, Mfg reccomends 2 1\2 turns on low speed needle but it was out 8 turns before it would even idle without a glow stick, Had some old hands at the field look at it as well and they have not been able to get it right either. Might be a defective motor. ???
Thanks for your help and I will try the other forum

Where is the engines forum I did not see it on the list.

One thing you failed to mention is the Make and size of the engine. Guys here have often experienced the same thing with an engine and can help diagnose the problem. You should always give as much info as possible.
Dennis-

It's got Tower Hobbies on it but I think it's an O.S. at least thats what it looks like and someone at the field said thats what it is.
.40 is the size and it has about 4 tanks of fuel on it. Never fails at high speed only at idle, when I throttle back for a low and slow pass. Most landings are dead stick

Thanks, Miloh.

Hay!!! how to use these stupid faces!!! :stupid: < See what I mean?

I had the same problem with a used engine I had... wouldn't idle down worth a darn. Tried everything except the basic - make sure all the bolts are snugged down! The back plate on mine were loose, once tightened the idle was right on at the original setting for the low end idle. Good Luck

Thanks I'll check it out

Miloh,
Not sure, does this engine have a low speed needle valve? Have you reset it?

Checked the o-ring under the carb.?
If your having to richen it up that much to run, maybe its sucking in too much air??
What markings do you see on the engine, where is the needle valve, front or back.
Have you tried different glow plugs?
What is the elevation of the fuel tank relative to the carb?
Using standard muffler or maybe a pitts style?

here is a picture of it, checked all the bolts and screws and all are tight. I will pull the carb next and check the O ring.
Can anyone I.D. this motors mfg. for sure?

It is a tower motor not OS and has a air bleed idle and they are hard to set! The screw on the right side of the engine skews in and blocks the hole in the front of the carb. This hole will be almost closed to get to idle. You must also have good compression with carb.

Engine forums are close to the top of the list of the many forums available.