That's kind of what I was thinking when I said I thought the 10X6 was a little small? (the altitude bit )

I live at about 500' though, so I have no actual experience in that regard.

Do you think an 11X6 would be more efficient, or just hit it with a bigger hammer? (put a bigger engine in it...I mean, that's the cure for everything, right!?)

If that screw was even a little loose, it was sucking air and going lean. I learned that little lesson after taking a carb, tank and all plumbing apart to inspect. It wasn't until I was putting the carb back together that I noticed the loose screw. A lesson I'll not forget!

I have a TT Pro-46 (with a Perry Carb) that I run 10%N (18% synth, 2% Castor lube) and it turns an 11X5 APC to 13,200 (on my optical tach) with 200 rpm backed off on the rich side for PMS (Piston Margin of Safety ;-)). It's a snotty little engine. I bought mine in the spring of 2002 and it has outlived one plane (hence the replacement carb) and been flown successfully in three others for various periods. I've run mostly 11X6 and 11X5 props, for pattern and IMAC style. Currently I have it in a 4-1/2 lb Goldberg Hot Stik and it is ballistic. I may have to try one of those 12 x 4 props.

300ΒΊ sounds about normal?!? I don't have a way to measure but in reading what others are finding in other forums that is a normal number for .40 to .60 size two-strokes.

Thanks for all your help, I have it running sweet at this point!

I am not sure which 1 factor was causing the problem, but it now runs like it should

Retightened engine bolts
Omega blend fuel
checked tank height
dissasemble and clean carb
checked exhaust pressure nipple

THANKS

871

Show871 et all,
One thing people often forget to look for or even think about is lateral pressure on the throttle arm - positive. With the engine running (throttle setting doesn't matter) pushing in on the throttle barrel will force the low speed needle a little closer to its seat. The throttle opening will remain pretty much unchanged but the fuel supply will be less causing it to run lean. (I'm sorry, "seat" may be a little misleading. Actually, I it pushes the low speed needle closer to the highspeed spraybar.)
I had a finicky engine such as this at one point and finally found the answer - the throttle pushrod was pushing laterally in on the throttle arm above half throttle causing errattic operation. I adjusted the throttle pushrod such that there was constant pulling force on the carb/throttle arm/barrel. It may sound strange but it worked. The thin spring sitting compressed behind the low speed needle is there to keep the throttle barrel pushed out. Any amount of force opposing it will defeat its purpose. Check the exploded view of the engine to verify its location.

It will only take a few seconds to check to see if this may be part of the problem.

I agree with the small amount of castor recomendation. I've had excellent results with Red Max (2% castor) and Wildcat Premium Extra. 5-10% nitro. K&B 1L plug.

Glad to hear you got it running well & Good Luck

Glad to hear you got it going.