3W 60 running inverted (Out of ideas)

[rc technics]

3W 60 running inverted (Out of ideas)

I have a 3W 60 long that I have had since 93 with a side induction card. Its has had very little running since I brought it all those years ago.

I am having problems with flying my new Yak 54 inverted. As soon as I roll I lose my power.

I have tried a number of ideas to fix the problem without success.

1) Fitted a carb plate over the diaphragm vent.

2) tapped a nipple and vent line from the diaphragm to the radio bay.

3) fitted a velocity stack within cowl.

4) Added air intake ducted from face of cowl to carb (tried with and with out velocity stack).

5) (Fuel tank sits about 4 in higher then the carb) So I tried a hopper tank right behind the carb.

6) Enlarged air exit holes for air within the cowl to exit

7) tried both 40-1 lawboy and 80-1 AMS oil mixes.

I am now simply about of ideas. Can anyone help?

[Bunky F. Knuckle]

Lean the low end needle out. This happens at a reduced power setting, half throttle???

[Dan767]

Tried replacing the diaphragm? I prefer using a 50:1 mix and Belray MC1 or H1R. Any good synthetic though, and mixed 50:1 is the most recommended ratio.

[rc technics]

I can hear the power change at full power but I notice it more at the mid range.

[Bunky F. Knuckle]

Lean the low end some. Go 1/8 turn at a time. You want the engine to just barely sag in a rapid transition.
It will kinda sound like a BUUUUUUUUUUUUUUUUUUHHHHHHHHHHHHHHHHHHHH. If you go too far, just open it 1/8 turn and should be happy.

Or fly it and tweek the needles that way. That is usually how I do it. Fly, and do a series of half rolls. If the engine burbles in the mid, then I know I can lean it more. You are looking for a constant RPM thru the midrange.

The low needle operates the carb up to about 67% opening. Then after that, the high needle takes over. I think once you get mid range set, the high needle might be ok.........