Hello All,
I purchased an AP Yellow Jacket .15 engine some time ago for an airplane I bought at the same time; the Aero Princess, by Sportsman Aviation.
My question lies with the engine. Why can I not get this little engine to perform? Following the manufacturers recommendations, I adhered strictly to the break-in procedures, ran the suggested amount of fuel, and followed the correct percentage of nitro content. With all of that said, I can not under any circumstances, get this engine to rev up anywhere close to where they say it should. I propped it with the recommended pitch prop for break-in, but now, almost two months later, it will not even spin a 7x6 prop up! What am I doing wrong? I know it is lean enough, and I know it is not too lean. The engine shows no signs of external wear, overheating discoloration, difficulty starting or anything else. It just will not run up.
Can any of you help me? After I broke in the engine sufficiently (actually more than the manufacturer recommends fuel wise) I put it in that Aero Princess whereupon it crashed because the engine did not have enough power. Since then, I have built another airplane that the engine would not even get off the ground! The last airplane weighed in under two pounds, so weight is not an issue either.
Please, if treating me like an imbicile is what is necessary to help me figure this out, then go right ahead. I have another one new in the box. I am afraid to use it for fear they are just useless engines.
Any help is highly appreciated.


Red