Hand Prop
 

My 337-H has been sitting in the hanger for 3 months while I have been away, and today I attemtped to start it (I know Mom).

I plugged in the oil / block heaters overnight to thin the oil, and then hand propped the front engine backwards several times and then lit it up. I then tried to do the same to the rear and it was "locked up" . I could prop it forwards, but not backwards.

When hand propping it forward it makes a miltiple click at one location on every revolution. I then ran it a few revs with the starter (no fuel) and it turned over fine, but again it would not turn backwards by hand.

What would casue this lock up, but only one way? Normally aspirated IO-360.

Any thoughts ? tks/Roger

The clicking is your impulse couplings on your magnetos and that is normal. Start to worry if you don't hear that noise.

The second last factory reman IO-360 I installed would not turn backwards. The starter drive was preventing it from going backwards. This was normal according to the engine shop who supplied the engine. After a couple hundred hours it could be turned backwards too.

Tony's probably right
 

I had a 65 Skymaster s/n 0028. Same issue, could not turn the rear engine backward. Found it was the starter impulse coupling on the factory reman I installed. You might want to consider pre-oiling by pulling the plugs then running the starter motor with fuel at idle cut off until you get normal oil pressure. Reinstall the plugs and fire it up.