3W 106 strange behavior

[thurmma]

And the saga continues...

This is 3W 106 iB2. Straight and level or inverted flight runs fine. No sag on verticals and will idle all day long then go. The issue is knife edge from left to right. When performing a right to left knife edge everything is fine, but when you turn around and set into the knife edge from the left, the engine goes lean, REAL FAST, like about 50 feet and it is sagging bad and it takes a few quiCk flips of the throttle from a level position to get it back to good running order. I have tried low and high speed passes and no difference. I am about at my wits end with this engine. Any help would be greatly appreciated.

 

[Husker]

Could be an unburnt fuel pooling issue in the reed block. Are you running a tube from the metering diaphragm the fuse?

I had 2 3w's with pooling issues and I put aluminum reed blocks on them and they ran great.

 

[thurmma]

Yes, I have a tube running to the fuse. It is only in a knife edge from left to right canopy in. Right to left works perfectly.

 

[Husker]

Yes, I have a tube running to the fuse. It is only in a knife edge from left to right canopy in. Right to left works perfectly.

If you have a plastic reed block that is likely the problem. They have a little shelf that fuel can sit on and then it gets dumped out in certain orientations.

 

[thurmma]

I also have the aluminum reed block and carb mount

 

[Husker]

That is nuts. I'd ditch it and get another motor

 

[thurmma]

It is getting close, but I hate it when something gets the best of me.

 

[Bunky.F.Knuckle]

Richen the low needle a hair. On a 3W transition, you want just the very hint of a sag (lean) from idle to full throttle. Too rich on the low, and you will puddle fuel. Too lean and you know what will happen.

 

[49dimes]

Fuel can pool at the back of the crankcase in the "lower" corner which would be the right side of the engine in your case. Being that the crank is also spinning to the right in relation to the pooled right corner it is easily picked back up in to the induction bath and gives a quench to the cylinder. I guess a good term to use would be "slugging".

So are you positive it is a lean condition causing you to sag???. I had similar issues with the old 3w 120 years ago. But for me it was in a harrier or hover and when going back to straight and level it would hick up and want to stall the engine.

 

[dhal22]

My 3W-106 (Blue head) purrs like a kitten. Of course it's had regular servicing by Gerhard. I had a couple of club members talking about it on Saturday, stopped me on the way back to my area to ask me what engine I was using.
Bunky F Knuckle is correct, a well running 3W hesitates just a little during transition.