IO-520D on a C185.

Getting ready to head out for Oshkosh. My starter has, on occasion, not turned when I try to start. Click, but no rotation. A few tries and it would eventually go. Replaced the starter contactor, same deal. Eventually figured out that turning the prop backwards would usually do the trick, so it seemed that the starter was suspect.

Today I got the starter back from the overhaul shop (well respected here in SoCal). I reinstalled it and went to start it. It barely turned over the engine, but then all was well until shutdown. Usually the prop stops and swings backwards slightly from the last compression stroke. This time it started backwards and stopped suddenly. It was very obviously different.

I got out and could not turn the prop backwards. Forward, no problem, but it was completely locked when turning it backwards.

I removed the starter once again and the engine turns freely as I’d expect.

I know that the starter adapter needs the starter to be able to unwind, so they say a max of 5 in-lbs of torque to be able to turn the starter. I don’t have a torque wrench that goes that low, but to my uncalibrated hand, this starter is pretty stiff.

Is this normal? Does a new starter loosen up over time? The last starter this shop overhauled (on a C180) worked perfectly right out of the box.

You should be able to turn the starter fairly easily with your fingers. I sent a new Energizer back to Hartzell because it was too tight (before I even used it), and when it came back it turned easily. It's worked fine ever since. I don't know what causes the tightness, but the Hartzell service bulletin says to check for this problem before installing any new or overhauled starter, and get it fixed if too tight.

Figured out the problem.

When the starter was overhauled, the starter shaft was shimmed maybe ten thousandths out of spec. As a result, it protruded too far out of the case, which caused it to bind when the nuts were tightened to attach it to the starter adapter.

Took the starter back off, the shop re-shimmed it and it’s now working like it’s supposed to.

Interesting----thanks for the follow up