National Aeronca Association Bulletin Board

It's time to 'fess up and share an experience that might save the rest of you some trouble down the road. Back in 2003 I installed a Skytec starter and battery system in my C85-12 powered Champ under a field approval. It has worked great up until recently. Back during the cold weather I was trying to start the thing when I experienced a "kick-back". Not always being the sharpest pencil in the box I tried again and it started normally. Since then I have noticed that sometimes the starter didn't seem as smooth as before and had actually made the decision to pull the starter and check it out. I ordered new gaskets and last week I went to fly it and it wouldn't start. The starter seemed to spin but the prop just wiggled a bit. Finally getting smart, I rolled it back into the hangar and got my tools and pulled the starter off. It was obvious that it was damaged - the gear was even missing some metal. I then got out my mirror and flashlight while pulling the prop thru and saw that a tooth was missing from the crankshaft cluster gear #$!!@&%$!

I called my mechanic and together we pulled the engine, removed the mags and the accessory housing and inspected the gear. Fortunately only one tooth was gone and I was able to fish it out of the oil sump with a magnet. There were some other metal filings in there as well but not too many. Further inspection showed the oil pump gears were OK and fortunately I had installed an aftermarket oil filter (TAF) which caught all the rest before it could damage any more of the engine. Whew!

Anyway, a new gear from El Reno Aviation (Nice folks) was $550 and a starter overhaul $250. The folks from Skytec were as nice as could be and apologetic about the damage the bad start had caused. They said the earlier design starters were designed to break rather than damage the engine and that my fractured tooth was a new one for them. They also said they redesigned the starter in 2007 so that it now contains a user-replaceable shear key so both the starter and the engine should not be damaged by a kick-back. For $250 they will overhaul and update your pre-2007 starter to the new design (which is essentially a new starter) and I would suggest you do this if you have an older Skytec. Check this link to see how to change the shear pin in the new design <http://www.skytecair.com/images/ST2%20S ... cement.pdf >

I don't blame Skytec for the problem. Cold engine, too much prime, in a rush.... it was pretty much my doing. Larry at their repair station has bent over backwards to take care of me and get a starter back to me ASAP so I can get my airplane together. I received two calls from him just today making sure all the details were "just right".

I thought I would share this with you so that others might be spared the trouble and expense that I have gotten myself into.

Tim

Tim

That is one of the problems with the Skytech starter-yours isn't the first to have that happen. I am putting a B&C starter on my Champ. They cost about $350 more but the starter housing is machined and not cast. Hopefully I won't have that problem. Talked to many folks and all suggested B&C as the Skytech had problems with the kick back although the B&C cost is more. As you know your time removing the engine and repairing it was more than the starter difference. You were lucky, others I have heard of ended up with an engine overhaul. BTW--Henry Klaus at El Reno is great to work with for parts.


Doug

The B&C is a fine starter, indeed all their products are well made. That said, I don't think they are immune to the problem of kick back. I took this from their own literature: "Unusually harsh operating conditions such as improperly timed magnetos that cause kick-backs during starting or sticking starter relays or keyswitches which cause the starter to remain engaged while the
engine is running may cause premature starter failure. Existence of these conditions should prompt corrective action and close inspection for possible starter damage."

Truthfully, I'd rather see the starter damaged than the engine. My hope is that the shear pin on the newer (and overhauled) Skytecs should help protect both.

Tim

Glad it worked out in the end.

The IO240 had the same problem. Continental issued a Service Letter on the problem. It,s usually the Bendix drive gear that fails. Glad to see you caught it in time.
Paul

Well,

We are building an RV7 and have an IO-360 ECI motor with a SkyTec starter.

A few years ago we had a long chat with Brad Dement from E Mag Ignitions at Sun n Fun and one of the things he mentioned was that in the design discussions for their ignition systems, they approached the 'new' starter people to talk about problems of shed teeth and broken castings.

Short story is that E Mag designed their system to wait prior to commencement of sparks - in other words I believe you see 3 blades and then it fires.

Stops backfires and damaged starters.

Check out the SkyTec website.

http://www.skytecair.com/EI.htm

I think that their units will be FAA PMA'd soon so you may wish to check them out.

We have 2 P Mags on our engine and after de inhibiting, it showed 3 blades and ran.........

On magneto'd engies with SkyTec starters I would be tempted to separate the starter and mags and go to the old fashioned method of initiating the start and then turning on the mags. easy to do with switches and a button. Sure, you may run out of hands but hey, we are dealing with old airplanes that are 'special.