How tight do I tighten the nut on my prop?

[picksbigwagon]

I was working on my boat today and I noticed that the nut on my prop was pretty darn loose. It is a 1989 40hp evinrude. It was loose enough there was a gap between the nut and the hub. I took out the cotter pin, and I could tighten it by hand, so I tightened it with a socket, and put the pin back in......did I do a no no???

[shouldbefishn]

The book on my Johnson 140 suggests 36-45 lbs of torque on the prop. Not sure on your motor but should be in that neighborhood. Maybe someone else could chime in on this one.

[Valv]

It is ok, you should keep it tight to avoid damaging splines on prop. It doesn't have to be torqued with a cheater bar at 500lbs, but it doesn't have to be loose neither, you did good.

[CatManLee]

Not sure if this is right or not, but I tighten mine as tight as it can go and still get to the slots for the pin to slide through. Now I wouldn't recommend jumping on the ratchet to get the nut turned more, just as tight as you can go within reason. My nut for instance is not tight at all. I cant tighten it, because it won't turn far enough around again to get the pin through, so it's pretty loose, but there's nothing I can do about that.

[picksbigwagon]

when I tightened it down I was halfway across the hole and I know if I would have leaned on it I could have gotten it past, but I eased it off a tad and put the pin back in.....

Good to know I didn't do a no no.....Valv, I should have known you would have been able to answer this......now if I can just find time to get out there and fish!!!

[DTro]

Does every motor have a hole for a pin? I recently replaced my prop on an 87 merc 25. I can't seem to find a hole for a pin.

[Valv]

Just few of the older ones, and smaller motors.

Nowadays most motors have a nylon self locking nut, you tighten it and it won't loosen up.

Also Mercury had some with a "tab" style washer, after you tighten nut you have to bend a tab to "lock" nut in position.

[Surface Tension]

dtro, not all prop shafts use castle nuts and cotter pins. In your case you'd have a lock nut and a tab washer that folds over one or two sides of your nut.

Some older outboards with prop nuts and cotter pins go on loose and you'll have play. In fact theres quite a few that use a plastic prop nut.

[Surface Tension]

I was typing away when you posted Val.