Michael G

My Feedback: (1)

My three month old Zenoah 20 has been a problem since it was new. Hard starts, bad idle, cut off when throttled back. After new rings and EI from Horizon the engine now starts and runs great while on the ground. Also runs great in the air, under power, in any orientation.......but put it in a down line and go to idle and the engine quits every other time, even with a high idle setting. On the ground or REMOVE THE COWL, and the motor will not cut off. Put cowl back on, dive and cut to idle, motor dies. Motor is on a FuntanaX 100. Motor installed inverted. Carburettor trumpet stick out of the cowl 1/4" to 1/2". YES I have installed fitting on carb air vent and ran a line way back into fuse. Fuse also has about a 3 sq" vent in back near stabilizer. NO I have not tried a closed balsa box, but I just can't believe air pressure/flow in mid fuse is the problem. Again, I can not make the engine quit with cowl removed. ANY IDEAS. One big pain in the a**.
Thanks, Michael

tkg

My Feedback: (1)

Fly it with out the cowl, if its OK then you got airflow problems

Michael G

My Feedback: (1)

Air flow problems where or over what???

Also TKG, didn't you have a 20 that you were having trouble with??

Turd

SHHHHHHHHHHH Jettpilot will be here soon LBB ------ I had same problem so I set the idle with the idle screw thinking I might have had some interferance or somethin, any way ever since I put the idle screw into play to adjust the idle two monthes ago the engine has never quit since. I also changed to a C H ignition as well and now my 2700 mah battery lasts for two days of flying

tkg

My Feedback: (1)

Air flow over the carb mouth/vent some where. Because all you changed was the cowl, not the ignition or fuel or carb.
I had a bad ring in mine that made for hard starting when hot and a poor idle. I installed a Bowman ring and things seem to be getting beter. But its been around 25 so havent gotten many flights in yet. Last run was an APC 17x6 @8600 rpm
TKG

merild

My Feedback: (37)

I have a G20 in a Seagulls Yak. I have trouble with a reliable ide it seems to surge a little and on 4 flights it quit 2 times when I idled back on landing hence 2 dead sticks out of 4 with a fast idle on the ground. I get pretty good performance with a 15x6 Evolution prop while in the air. I need help on idle, I removed the velosaty stack as it would have to stick out the side of the cowl.

lou1947

If its surging you are probably running a little lean on the low end. Try richening the low (Shorter of the two screws) by 1/8 to 1/4 turn.Hope that helps let us know what it does.