ST 90 Problem
 

Hi Looking for suggestions. Have a ST90 btoken in and run for many many flights over the years on 15% nitro fuel (20%oil). Ran a 13 x9 APC prop inn a king kobra. Now trying it in pusher configuration with both 13 x8 and 12 x 8 prop. No real peak on the high end with mixture adjustment (very broad) and then quits lean. Low end similar. Very hard to adjust so that it will run let alone well and transition. Have tried the proscribed method of setting carb. tried several differnet temp glo plugs incldugin OS 8 annd 3

Thanks

RE: ST 90 Problem
 

Put the engine on a test stand with a regular tractor prop on it and see how it runs. It just may not be getting enough cooling in the pusher installation. That's a common problem with pushers.