Bleh...

These engines run just fine once you take off the limiters.

Don't believe those who tell you otherwise when they don't EVEN own one... sheez.


mdfogg:

It's obviously leaning out when nose up.

So the first question is does it do the same at full power when level?

If the answer is no, then EITHER the high end is too lean OR when it is pointed nose up something ( plumbing ) is causing the engine to lean out...

DO remove the limiters not just the "pins" but the whole aluminum collar and screw if you still have them on.

Try pointing the nose up, with about 1/2 tank of fuel in the plane, with the engine running... then CAREFULLY adjust the HS needle richer until you hear the engine slow down just a touch... leave it this way and keep holding nose up for another 60 seconds... It must NOT cut out...

You should NOT get any bubbles until the tank is very low or you point the plane nose down!

Bubbles either indicate an air leak or vibration is introducing air bubbles into the clunk. Did you wrap the tank in foam?
Have you tried one of tho Dubro anti-foaming/bubble clunks which help a lot.