bigben

My Feedback: (24)

The engine this a 3W 75US. The problems are many and I'll try to make them clear so you can share thoughts, experiences and recommendations before I make an anchor of this engine. I bought it used and can't document exact amount of use but must be several gallons.
The engine primes poorly but has great compression. Once running the low end is very rough yet top end power is very good and steady. Mid range seemed OK. Fuel spits from the carb at all times and have attempted to run in the low needle to smooth out the idle. I found it runs with the needle all the way in while still spitting fuel. I put a fuel line on the vent connection and ran it into the fuse but it collected fuel in the line. The shop said they rebuilt the carb but suspect an air leak and maybe the float lever is out of adjustment. I can't attempt to fly an engine in this condition and need help.
The engine has made two trips to AZ to a shop named after a desert plant and they were not enough help and have gone mute in my recent request for help.
Any ideas?

waynem

My Feedback: (58)

Hi Bigben, I have a zenoah 23 that was spitting fuel from the carb. and the problem was the needle valve arm was to high and letting the carb. flood. If you are getting fuel into a tube hooked to the plate above the needle valve then the diapham must have a hole in it. The control arm should be about level with the carb. body or a little below it. They make a gauge to set the height of the arm . Hope this helps you. Wayne

Antique

My Feedback: (4)

Leaky reeds...Reeds don't close off the crankcase pulse...Pushes fuel back out the carb...Not unknown on 3W engines.....

rc bugman

My Feedback: (30)

The poor sealing reeds are the problem. If the reeds are curled, just flip them over. You may have to redrill a hole or 2 in the reed mounting area. If the reeds are shredded, call Gerhard at Aircraft International.

Elson

bigben

My Feedback: (24)

Thanks Guys.
Wayne - the float lever was above the body and on this past Saturday I had bent it to be even with the body but the spitting continued and the reeds might be contributing as the others mentioned.
The reeds are yellow in color and kind of a phenolic material. I am not that familiar with reeds so do they sound normal or old style? I didn't detect any warpage as Ididn't think the plastic could warp. Maybe I need to look again or flip as was mentioned.

It's wet and cold here again this weekend so I should be able to get some garage time to run it and try these tips out.
Much appreciated.

bigben

My Feedback: (24)

I bought a carb kit and think the local saw shop had their way with me ($19.26). Made sure all passages clean, etc.
Engine mow primes as it should and started better. Both needles now effective at changing mixture whereas before only the high made a difference.
Still spitting fuel but now only at idle and the idle gets way too fussy at and below 2000 RPM.

The reeds are yellow plastic type. Could not see any warps or splits. Can someone tell me more about the reeds or the aluminum replacements through Gerhard as I hope that settles down this power house?

Cheers