New to mud motors. I have a 27hp GDSD with a three blade prop I bought used. My question is does the nut on the end of the shaft have to be touching the prop? Mine is about 1/8" away from touching the prop and there does not appear to be any retaining pin for the nut. Is this how they are? Thanks.

If you are talking about the nylon nut on the end then no. It doesn't need to be up against the prop but won't hurt if it is.

As you hit debris, the prop tightens on the shaft, so it goes away from the nylon nut and more towards the stop nut behind it.

Maybe you had some play in the prop, which you are suppose to have, and it's just tightened down on the stop nut.

You may want to go ahead and hit the prop with a rubber mallet and see if it still turns freely. Cause when it's time to replace the
Prop, if it's stuck on the shaft, it'll be a whole lot of fun getting it off.