Ike cleared out early this morning now we have a beautiful day here in East Texas. Too windy to fly but just right for engine testing. Gave it another shot. Same thing, can not get a reliable idle or full speed. After spending a full tank adjusting, I shut it down to think for a while.

While watching the pregame show, only thing I could think of is maybe ignition. I have another ignition module so I was thinking that I might try it. But then I thought, it just seems like the engine can not draw fuel properly. What could cause that. I know it is not the carb because I have gone through it completely. Then I thought, also before I started all this, I was having a problem with interference so bought a resistor plug. The plug I bought was a RDJ8Y. The original plug was a DJ7Y. Pulled the plug out and compared it to the DJ7Y. The 8 does not go into the cylinder as far. So I thought maybe the 8 was letting the compression down by not sticking as far into the cylinder. So I stuck the 7 back in.

Fueled it back up and headed out into the yard. Needless to say, It improved immediatly. I could adjust the low speed needle to get a reliable idle and good transition. However, the engine would peak just before hitting full throttle. Keeping in mind that I do not have a throttle stop for WOT with the lever swapped end to end, I adjusted the end point on transmitter until the engine peaked at the same time the stick reached full on my transmitter. Engine is running perfectly now but now the glitching problem is back. Will have to order me a RDJ7Y plug to get rid of the RFI glitching.

I tached the engine with my Tower tach. Dont know how accurate it is but the engine sounded like it was hitting peak rpms. Using an APC 17x10 prop, I tached 6700 rpms at wot. and idle was at 2400 rpm. I grabbed the tail of the airplane to see how hard the engine was pulling and it felt like it had lots of pull. I dont know if this prop loads the engine more than the benchmark prop of 18x6. I have read that 18x6 should do around 7k to 7400 rpms. How does this compare in load to the 17x10? Dont have enough ground clearance to use an 18" prop on this plane.

Anyway, it felt good to get the engine running properly after struggling with it for over a week. Eventhough I still cant fly it until I get that resistor plug.


Jim