I had issues with the FA-180/FG-57 CDI hybrid power output.
It would only pull about 7500 RPM @ WOT with an 18X8 prop. That is about FA-150 power. I popped the rear cover off & inspected the rear main bearing.
It only had a slight patina & was smooth, but the cage was not following the balls around the inner race. I pulled the engine, installed new bearings ran it on the engine stand. 8250 RPM (about 3.3 HP) with the 18x8 Dynathrust propeller! Dependable idle was 1100 RPM on the stand with the cylinder mounted upright.
I mounted the engine on the airframe & that's when I stated having problems with getting a dependable idle with smooth transition. If I would lean out the LSN for good idle, it would spit & fart on transition.
I fought it for 2 days until I remembered something I learned a while back.
A dab of
SILICONE GREASE IN THE MCDANIELS PLUG SOCKET allowed me to lean down the LSN & still get smooth transition from 1500 RPM idle.
Taxi tests done yesterday at the Seaway Valley Modelaires flying site allowed me to further refine the idle/transition by leaning out the LSN about 1/8 turn more. We also tested fuel delivery at vertical, inverted *& nose down attitude at various throttle positions & transition. I held the plane while a friend jockeyed the throttle. It has enough power to go vertical from a hover on the upline!
I still had an issue with the throttle trim being way too sensitive gaining several hundred RPM with a single blip on the digital throttle trim. Last night. I investigated the EPA on channel 3 & found that it was turned way down to compensate for an overly long servo arm. I shortened up the arm & it now has nearly 125% EPA W/O stalling the servo. I also adjusted the pushrod so that the idle position had the arm back beyond 45* so that there would be less linear motion on the pushrod for a given amount of rotational motion of the servo arm.
If the weather hold for today I'm going to the field for more taxi tests & possibly a maiden flight if my expert pilot friend can make it out. I'm still too shaky to risk flying an unproven aircraft. A little more stick time will restore my confidence so for right now I will have to observe & fly on a buddy box.