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Engine Idle Problem
Posted: Wed Sep 13, 2023 8:53 pm
by simonlowther
Hi all
My C120 has an idle problem. it is fitted with the C85-12 engine and Stromberg carb.
When I pull the throttle to idle I get a beautiful rhythmic tick, tick, tick at 650 RPM for about 6-7 seconds, then she dies. If I am fast enough a (small) burst of throttle will keep her going. It feels like it is running out of fuel?
Any suggestions?
At all other power settings everything is running well.
Much thanks
Simon
Re: Engine Idle Problem
Posted: Thu Sep 14, 2023 9:46 pm
by 6298
Try turning the screw on the back 1/2 turn to the left, and see if it helps. Counter clockwise here, not sure about New Zealand.
Re: Engine Idle Problem
Posted: Fri Sep 15, 2023 6:47 am
by 7392
Simon
I think Randy has the answer to your situation. Several years ago, on my after annual test flight, my 140 with the same engine
and carb, would quit on landing roll-out. I started at a quarter turn to the left, but ended up at a half turn. No problems with
the idle since then.
Hope this helps.
Larry
CESSNA 140 1946
89011
Serial #8015
R26 JACKSON COUNTY TEXAS
Re: Engine Idle Problem
Posted: Tue Sep 19, 2023 7:08 pm
by simonlowther
Today with my mechanic we adjusted the idle mixture one half turn rich and now its purring perfectly.
Much thanks
Simon
Re: Engine Idle Problem
Posted: Tue Sep 19, 2023 7:33 pm
by tonycondon
idle mixture adjustment procedure from the Stromberg Specialist attached. I usually have to re-do this in the spring and fall.
Re: Engine Idle Problem
Posted: Wed Sep 20, 2023 6:14 am
by 7392
From my previous reply.....If I recall, the guy that did my annual that year, had adjusted the idle screw
'by the book' but the result was engine quitting on landing roll-out. Sometimes the "BOOK" may be off.
These STROMBERG carbs have a personality of their own.....plus they can't read.
Larry Surratt
1946 CESSNA 140
89011
Serial # 8015
R26 JACKSON COUNTY MUNICIPAL AIRPORT