Hi all
I have a pipded  os 32 f with .275 venturi K&B needle,tank is plumbed with the uniflow tube just above the center line of the venturi, I added a head gasket blocked the boost port and the pipe is set at 15.5" , today was its first time out I launched at 10,200 and it performed perfectly for about 3 min then it sped up for about 1 min then settled back in to a peerfect grove then started to surge and quit with about a 1/4 tank left.
I don't think it's supposed to do that...lol Any ideas?
Thank you
Dwayne

A 17.5 pipe lenght would be closer than the 15.5 you set it at.
Also you may want to unblock the boost port

Randy

You've checked the obvious things? 

• Tank doesn't leak (try pressurizing it and holding it under water)
• Clunk goes all the way to the outer wall of the tank, and moves up and down it easily
• No pinholes in the fuel tube
• Fuel isn't foaming

(I'm not good for any more advanced suggestions).

I found it helpful with a recent problem to start the plane up and hold it horizontal, outer tip down, to simulate flying the circle.  This let me watch the fuel system and see where the fuel was, whether it was foaming, how the bubbles were coming out of the uniflow, etc.  It helped lead me to what I hope is a solution.

Thanks Tim, when I installed it I was carfull that everything was ok but I'll be going through the whole thing again.
Dwayne