Mailing List flyrotary@lancaironline.net Message #46112
From: Bobby J. Hughes <bhughes@qnsi.net>
Subject: Starter Problem \ Question
Date: Mon, 11 May 2009 22:35:59 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Is it possible for a starter to keep drawing current after engine start without being engaged to the starter wheel? I was seeing a 38A draw today during ground runs with only fuel, spark, EM2/3 and engine monitor turned on. Normally I see about 15A in this condition. During ground runs last week and running on my backup battery\ wiring I popped an 80A ANL fuse several minutes after engine start. At the time I suspected a hot polyfuse in a crowbar circuit for the alternator triggered the event. After studying my wiring diagram I determined the crowbar opening could not cause the fuse to fail. The only item capable of blowing this fuse is the starter. The starter coil wire is in parallel with a firewall contactor coil wire. Both coil wires go to a starter switch fused at 10A. I suspect a starter problem is keeping voltage on the coil lead and keeping the firewall contactor closed after engine start. My firewall contactor is not the usually starter contactor with the small wiring terminal for the starter. It's a conventional contactor but rated for high current. This may be part of the problem. If the starter checks out then I will use a DC amp meter on the starter lead. I may also add a run-on light to the coil leads.
 
Any input would be appreciated.
 
Bobby
 
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