Mailing List lml@lancaironline.net Message #60692
From: paul miller <paul@tbm700.com>
Sender: <marv@lancaironline.net>
Subject: Chapter 5 ISKRA starter and failed starter adapter
Date: Fri, 13 Jan 2012 15:22:21 -0500
To: <lml@lancaironline.net>
Uggh, probably 6 weeks down but I've lost count.   So, the next lesson is not to try to start an IO-550 with less than perfect batteries.  A slipping starter adapter will really get trashed if the voltage is insufficient to wind that spring on the starter shaft and grip with enough friction to turn the Continental over.  If the voltage is down and the grip starts to relax then the slipping can start and progress to failure.    That's the beginning of the story this past summer when I had hard starting and the batteries started to weaken while I was in a rush to get going.

In the last chapter, I had ordered and installed a Niagara replacement starter adapter and watched it crack open within 3 blades turning.   Niagara strongly suggested it was my mags that caused the problem so they were sent out and reported to be in excellent condition for 500 hours.   I decided to return the failed adapter to Niagara who kindly offered to take it back including shipping (thanks) and start to repair my existing adapter.  The unit was inspected and the starter shaft was indeed worn below limits and sent to Aircraft Specialties in Tulsa where I'm told it will be re-ground to a M15 size and a new undersized spring installed. The Tulsa shop comes highly recommended by Skyteck starter folks.   The web pricing for grinding is about $75 for the shaft, $50 to turn the worm wheel and $250 for a new spring.   Hopefully, this will put the engine back into operation combined with the new (old style) TCM starter.  I will note that my hangar partner removed his ISKRA and found the drive end to be unmovable with fingers so anyone with an ISKRA should at least be aware of what is happening and get it changed under warranty if possible before you fall into this situation.  Starting with weak batteries can also lead to accelerated slipping from my experience.  I will report once the starter adapter is returned to service, the engine is re-mounted and the cobwebs are swept from the cockpit.

Paul
Legacy


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