I recently bought an airplane with a YS 91 AC with Aluminum cone. I removed the cone seeing 2 nuts on the prop shaft. First nut came of easily. Now the 2nd nut wont come off. Since the prop spins freely I cannot remove the 2nd nut because there is no backplate for the nose cone like on my trainer. Do I need to use a piston stopper? I really don't want to have to use one if I can avoid it.

Please advise.

Thanks.

The problem is that the nut holding the prop is bottomed out against the base of the threads on the shaft or the drive washer face is worn smooth. Unfortunately, grabbing the drive washer with a pair of pliers is probably the only way to get the nut off. This is ultimate tacky way to do it. The drive washer will have to be replaced when you get done.

DON'T EVER USE A PISTON STOPPER ON ANY MODEL ENGINE!!!!!
It's a clever invention designed to cause damage to your piston.

If you can't get this handled yourself, send it to YS Service and we will get it apart.

Good Luck

Dave

In the past I have had similar situations. I used an old leather belt and cut a strip about 3/8 inches wide. Wrap this around the drive washer, and use Channel lock pliers to hold the drive washer. The leather will protect the finish on the drive washer.

Problem solved ... thanks for your help.