Dave Harmon

Bax....I've been researching on RCU some of your comments about the regulator diaphram going stiff.
I'm having a surging problem and the engine is down on power.
The bearings, all O rings and gaskets were replaced this week with no improvement. Valves are set to .003 and the seats dont leak.
The ring end gap is about .003 also.
There is no trash in the needle seat or throttle barrel.
Is it possible to soak the regulator in raw fuel to 'un-stiffen' it or any thing I can do to fix it other than buying a new housing?
The engine only has 30 or so flights on it and it has always been run on CP heli fuel.
When it runs...it's very strong.

DH

Bax

My Feedback: (11)

On other pumped engines, it would take 2-4 14-ounce tanks' worth of running for a regulator diaphragm to loosen-up. Also, surging would mean that the engine's too rich. You may want to just run the engine a bit at full throttle and work with it. Other than that, the carb/regulator would have to be sent in for servoce.

Dave Harmon

Thanks Bax.....I set the throttle to full, opened the needle valve all the way, then removed the glow plug and used the starter to spin the engine to get fuel all up and in the pump and regulator. Then I removed the carb and soaked it in fuel all day keeping the regulator submerged in fuel. Then, re-assembled it and the engine ran very strong like before....no surging or any funnies at all.

DH

Bax

My Feedback: (11)

Glad you got it sorted out.