Engine Idle Problem

[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

[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.

[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

[simonlowther]

Today with my mechanic we adjusted the idle mixture one half turn rich and now its purring perfectly.
Much thanks
Simon

[tonycondon]

idle mixture adjustment procedure from the Stromberg Specialist attached. I usually have to re-do this in the spring and fall.

[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