Was just tuning the 80GK with a 13x6 prop and it makes a BIGdifference in rpm. It peaked 10,100 on the last run but, the idle is only 2200 to 2300 rpm. It's also surging at peak rpm and haven't figured that one out yet but, on the last run it seemed to be steady. I've been filling the tank about 1/2 full and it's down to about 1/8 tank now. Seems strange to me how it peaks higher when the tank is almost empty. I'm stil not happy. Maybe a carb overhaul will help. Don't know how much time is on the engine but, it appears to be low. Paint is still in excellent condition, it's very clean, and compression is high. Of course, Idon't know how long it's gone unused either.
I'm going to change the plug as soon as it cools down and see if that will help. It can't hurt. I pulled and tested the plug that came with it and it glowed good and hot right away so Ifigured it was good to go. However, it has died a couple of times when I pull the igniter off.

The HSneedle is approx. 5 turns out and the LSis just about even with the end of the throttle barrel. The transition bogs down a about mid throttle but, picks up again if Iopen up at moderate to slow speed. If Iopen it fast it dies or tries to die just above idle.

Haven't had a chance to start the 80s with the TH. That's the one that had the large rpm drop. If I can get the GK tuned I'll tackle the other one tomorrow.
I need to go to another LHS that's better equipped and buy 2 good 13x6 Xoar props. I don't like blunt ended props.

Garry