nonstoprc

My Feedback: (90)

Hi,

I have a RCS180 which has just been broken in. When it is warm, the engine tends to run only about 3-4 seconds after being fired up. When it can run (after say 10 start attempts), it can run pretty decent on the ground (8200 RPM on Menz 18X6). In the air though, it has the tendency to lean out.

The first flight (i.e. when the engine starts cold) is always good (easy to start and no lean out in the air).

The ignition battery (4 cell 1100 mAH sanyo) is pretty new and checked OK. The ignition switch is the heavyduty MPI name-brand.

Any suggestion on the cause of the problem?


Thanks QC

Mike Dooley/RCS

richen the H and L needles at least 1/4 turn. You also might have an airflow issue disturbing the carb inlet causing the mixture to change.
Thanks,

nonstoprc

My Feedback: (90)

Hi Mike,

I did some additional testing and found the difficult-to-start problem can be reproduced even when the engine is cold, provided that the ignition battery's voltage is at about 4.8v (fully charged and then discharged with a Triton charger at 0.6A for about 20 minutes). This pretty much simulated ignition battery's state (actually 2 flights, fully throttle). The battery was capable of deliverying [email protected] for another 40 minutes. I also compute the max voltage drop caused by internal resistence (Sanyo KR 1100AAU, 19.0mΩ): 19X4X0.6A=0.0456 v. Looks like this should not drop the working voltage below 4.5v (the min specified by the instruction). Sounds like the iginition module is at the fault?

I've also played with H and L needle setting (not much help). The "air" gap bwt the firewall and the carb is 1".

Thanks again. --QC