karolh

My flying buddy is having problems with his 3W140 and having no internet access at the moment has asked me to seek help on his behalf.

The 3W140 is in a Godfrey 300L turning a 30x10 prop on 40:1 fuel and has developed this problem.

It used to turn 6100 on the groung routinely, but now suddenly, it only go from idle to about 2/3 of full throttle ( 5400) if throttle is advanced slowly. Any attempt to advance the throttle further results in a shutdown. However, if the engine is quickly throttled back it will continue to run.
Here is a list of things we have checked so far.

1 Stripped and cleaned carb....nothing found wrong and no change.
2 Opened HS needle from 2 1/4 to 3 turns...no change.
3 Checked ignition module on a 3W120...works perfect
4 Checked magnet sensor on 3W120...works perfect
5 Checked all fuel lines and plumbing..everything found ok
6 Changed voltage regulator (6v to 4.8v)...no change
7 Removed cylinders and cleaned a thin film of carbon from pistons and cyl. head
8 Checked for sticking or broken rings....all ok
9 Checked that butterfly is opening fully

The engine has very good compression, starts easily and will idle down to 1600. Please help as we are at your wits end here.

Antique

My Feedback: (4)

Try flexing the carb diaphragm..If it's at all "crinkley" it's no good...

karolh

After dismantling the carb again to check on the condition of the diaphragm which is okay, we just happened to notice that the spacer block between the carb and the engine is severely warped. We plan on using high temp Red silicone as a sealer between the mating surfaces and see if that solves the problem.

Kris^

My Feedback: (1)

You might actually have a kinked or restricted fuel line. I've experienced this a couple of times, and the carburetor will actually pull gas through a kinked line up to full power, at which point the engine starves for gas and shuts off. Fuel line can kink, and it not be clearly evident without a really close look.

Hope this helps.

bob_nj

My Feedback: (62)

Wasn't this problem figured out on the [SA] list? It was a warped phenolic block. Kris, do you know of anyone that converts the DA bloc kto fit the 3W? I have a 140 and a DA block but don't have the experience to tackle it. Thanks_bob

Kris^

My Feedback: (1)

HAHAHAHH. . FUNNY you should ask. . . . . . .

I did it to my new-style 3W150 about 15 months ago, and the engine has run perfectly ever since. .I EVEN took pics of the process. . .

Maybe I should do a "how to" on it

bob_nj

My Feedback: (62)

I'd pay for that!! What was the hardest part of the process, and what are the tricky parts?

Kris^

My Feedback: (1)

I'll post a writeup and pics on this forum, Bob. . give me till tonight

bob_nj

My Feedback: (62)

Thanks. That would be great. As far as I know DA only makes one block for the don't they?
I got mine last year at the WRAM show. Take care_bob