SkyTec starter failure question

flyeyes · #1 03-10-2006, 08:39 PM

Hi All.

Earlier this evening, my SkyTec starter failed with a little over 100 hours when I tried to start and taxi away from the fuel farm.

The starter would turn the engine through 2-3 blades, then disengage (prop would stop but you could hear the starter winding up). As the starter slowed over a 2-3 second period (with the button released) it would suddenly "catch" and bump the prop another blade or so.

I uncowled the engine and pulled the starter off, and it looks grossly normal--no obvious problems like some I've read about.

The teeth on the starter look OK, and the ring gear looks slightly "chewed" on some of the teeth, on their aft edge (really slight-not noticeable unless you're looking for it).

I'm running an IO-360 angle-valve with one Bendix impulse mag and one E-mag. The prop is very lightweight (WW 151).

I've never had a starter fail this way. Is this typical? Other than mailing it back to SkyTec, any other ideas?

Thanks in advance

James Freeman

tin man · #2 03-10-2006, 09:08 PM

Either the starter is loose, the starter case is cracked, or the throw out bearing is worn. One way to isolate the problem is to remove all electrical ignition sources ( remove spark plug wires etc) crank the engine and see what gives. I had to do this on my previous RV with an early model Skytec starter. In my case the starter case was cracked at the throw out bearing area and was not noticeable until cranking the engine and seeing the bendix gear deflect at the throw out bearing.. Be careful.
Tom

gmcjetpilot · #3 03-10-2006, 09:19 PM

Any other symptoms, kicks? Check the impulse is working and that the non impulse is not hot during cranking. Good luck. George

flyeyes · #4 03-10-2006, 09:41 PM

Quote:

Either the starter is loose, the starter case is cracked, or the throw out bearing is worn.

Kind of what I'm thinking, but nothing really obvious. The starter definitely wasn't loose, and I don't see any cracks. I'm not going to fool with it much--I'm leaving on a two week trip tomorrow so I'll send it back to SjyTec and see what they say

James

osxuser · #5 03-10-2006, 10:12 PM

If it's a skytec, it doesn't have a bendix... But i'd guess an intermittent connection to the solenoid...

John Fisher · #6 03-11-2006, 11:45 AM

Quote:

Originally Posted by flyeyes

Hi All.

Earlier this evening, my SkyTec starter failed with a little over 100 hours when I tried to start and taxi away from the fuel farm.

The starter would turn the engine through 2-3 blades, then disengage (prop would stop but you could hear the starter winding up). As the starter slowed over a 2-3 second period (with the button released) it would suddenly "catch" and bump the prop another blade or so.

I uncowled the engine and pulled the starter off, and it looks grossly normal--no obvious problems like some I've read about.

The teeth on the starter look OK, and the ring gear looks slightly "chewed" on some of the teeth, on their aft edge (really slight-not noticeable unless you're looking for it).

I'm running an IO-360 angle-valve with one Bendix impulse mag and one E-mag. The prop is very lightweight (WW 151).

I've never had a starter fail this way. Is this typical? Other than mailing it back to SkyTec, any other ideas?

Thanks in advance

James Freeman

Hi James,

I also had exactly the same problem as you with my new O320 after about 100 hours, I guess the same time that compressions are starting to settle down. the answer yes you have alreaday guessed it, I had grounded the right mag instead of the left one *#@! I just could not believe it. I replaced both the Starter and the ring gear 180 hrs now and no problem.
I could not believe that I had mistaken the right and left mag ground leads.

Regards
John Fisher

osxuser · #7 03-12-2006, 10:29 AM

You run the impulse on the right? Thats kinda weird, most people run it on the left. (based on how bendix switches ground mags)

flyeyes · #8 03-12-2006, 02:56 PM

To respond to a number of replies:

I'm running a Bendix 1200 series mag with an impulse coupler on the left, and an Emag (which also retards the spark for starting) on the right. Timing is good on both sides.

There was no "kickback" associated with the failure, it just seemed to unhook from the ring gear after a couple of blades (prop stopped, starter wound up in pitch). I immediately released the button, and the starter started winding down. Just before it stopped, it "caught" and bumped the prop through one more blade. My first though was that the starter was not tightly bolted to the case, but it looked normal after uncowling, and all bolts/nuts were tight. Electrical connections were all good.

I'll see what SkyTec says.

James Freeman

rv8pilot · #9 03-12-2006, 05:22 PM

It seems like the starter does not engage the ring gear proberly,had a piper with the same problem,take the starter off/or the ring gear and run the starter too se if the starter gear goes all the way forward so that the starter gear engages the ring gear correctly,dont know if you understand what I am saying,but if gears does not overlab correctly,the ring gear will wear and the starter will disengage.

J?rn M?ller
RV8 208 hours

flyeyes · #10 03-22-2006, 01:29 PM

Finally talked to Skytec today (I've been on the road for a week and a half).

They say that the starter was damaged by a kickback and is not warranted.

I was aware before I bought it that the SkyTec was particularly vulnerable to this type of damage, but I thought that I had set the airplane up in such a way as to avoid the possibility (One impulse mag on the left, and one Emag, which retards the spark for starting, on the right). SkyTec specifically excludes warranty coverage on electronic ignitions other than the Emag. It appears to me (from reading other posts over the years) that this type of failure is fairly common with the SkyTec, and is not warranted, no matter how the airplane is set up.

Fortunately, the repair is fairly cheap in airplane terms, (around $100, with shipping), but I probably would have been better off to buy the pricier B&C starter off the bat and avoid the problem entirely. Fixing it for now is the quickest and cheapest way back into the air, but one more failure and it's gone for good...

I don't know of a good way to test an impulse mag other than listening for the "clunk" as I turn the prop through, but I'd be eager to learn.

I know a lot of people have had a good service history with the SkyTec, and I hope I will after it's returned, but I'm feeling a little stupid and annoyed right now.

/rant off
ADDENDUM: See post below: Basically, the guy delivering the bad news was the repair guy, not one of the prinicipals in the company. When he ran it by his boss, the word was that if an Emag was installed, it was a warranted repair, end of discussion. This is how things ought to work, although they often don't. They made this call before I even had a chance to call back and hastle them or escalate.
James Freeman