Hi Everyone,

Tom,

I am glad you created this thread very helpful. I am looking into purchasing a 7-77 for an AT-6 Texan, its a used engine that has not been completely broken in. I have a couple questions; 1: You mention old vs new carb that deals with the richer setting at idle. I have the serial number to the engine I'm considering, is there a way to determine if this engine has the old or newer carb? 2, when breaking in the engine the original owner used 5% nitro & 9% oil during the process, do you think the nitro had an adverse effect on the engine?

Any help is much appreciated, Mark