Mag check parameters

by Wendell Hamilton in General Tech Discussion 8 years ago

I'm new to the 912ul, just bought a older coyote ii 80 hp. I did my first mag check the day after I purchased and my mag check concerned me. One mag had maybe 50 rpm drop the other had 200 rpm drop @ 4000 rpm. I understand max 300 drop but I also read 120 rpm max difference.
Would this be considered acceptable?
Any insight would be greatly appreciated
Thank
Wendell

Re: Mag check parameters

by Roger Lee » 8 years ago

Roger Lee

131 5.38k 5.44k

If I were you especially just picking up a used plane with unknow use and wear in this circumstance I would change the plugs. Gaps to be set between .023-.027. .025 is in the middle.
Then unscrew the plug rubber caps and then trim the plug wire back 3/8" and screw the plug cap back on. you can put some die electric grease on the ends of those plug wires. Then do your mag drop check again. Don't look for exotic problems because most times it is something simple like the two items I just suggested.

You can while you have the plug caps off Ohm out the 5K resistor in the cap with a meter.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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