Need Help: Prop Shaft Jam Nut Won’t Budge

[testingthewaters91]

Hey everyone,
I’m working on my 1981 Hunter Cherubini 30 and trying to remove the jam nuts on the prop shaft. I already pulled the cotter pin, and I need to remove the tall nut and the locking nut — but they just won’t move.

I’ve tried gripping one with a spanner wrench and the other with a pipe wrench, turning counterclockwise, but they won’t budge. I’m starting to damage the flats and don’t want to ruin anything.

Any advice? Heat? Penetrating oil? Am I missing something obvious? Appreciate any help from those who’ve been through this.

Thanks in advance!

 

[heritage]

I would first remove all of the old bottom paint from the crevices around the nuts and then try squirting in some penetrating oil like pb blaster.

 

[Don S/V ILLusion]

If PB Blaster doesn’t work, head and some long wrench extensions are your friend. You will also need a gear puller just like as with your wheel problem.

 

[garymalmgren]

Small grinder with a cut off disc.
Carefully!!
Gary

 

[dlochner]

Remove all the paint, penetrating oil, then heat.

Remove the shaft from the transmission and take the shaft with prop attached to a machine shop and have them work their magic.

Is this a bronze shaft or SS? If it is bronze it should come out and checked for wear in the cutless bearing and at the stuffing box. It may be necessary to cut the shaft to get it out of the boat.

 

[testingthewaters91]

Remove all the paint, penetrating oil, then heat.

Remove the shaft from the transmission and take the shaft with prop attached to a machine shop and have them work their magic.

Is this a bronze shaft or SS? If it is bronze it should come out and checked for wear in the cutless bearing and at the stuffing box. It may be necessary to cut the shaft to get it out of the boat.

I just wanted to switch the places of the nuts, because I know the jam nut is supposed to be on the inside.

Are all these extra steps necessary?

It's a SS shaft.

 

[testingthewaters91]

Small grinder with a cut off disc.
Carefully!!
Gary

I was hoping to just take them off and switch their places to the proper places as they're only 2 years old.

 

[testingthewaters91]

If PB Blaster doesn’t work, head and some long wrench extensions are your friend. You will also need a gear puller just like as with your wheel problem.

Why will I need a gear puller? I thought I would just unscrew the nuts and screw them back on in the correct order.

 

[Tally Ho]

Why will I need a gear puller? I thought I would just unscrew the nuts and screw them back on in the correct order.

I think Don is thinking you are pulling the prop off….hence the gear puller.

I would try 2 pipe wrenches if you can get one on the thin nut…and as others have said, try to clean the paint off the treads, and use some penetrating oil. You can certainly try heat as well.

Greg

 

[jssailem]

The prop may not come off easily once you get the nuts free. Puller makes it easier.

 

[pgandw]

I’ve tried gripping one with a spanner wrench and the other with a pipe wrench, turning counterclockwise, but they won’t budge. I’m starting to damage the flats and don’t want to ruin anything.

Any advice? Heat? Penetrating oil? Am I missing something obvious? Appreciate any help from those who’ve been through this.

About 4 months ago, I couldn't bust loose a spindle nut on a mower deck I had to repair. All the online instructions said the nut could be difficult but it would release. I notice all of them were using impact sockets with either electric or air impact drills. So I went down to Lowe's and found a battery powered impact drill for $70, and got the appropriate impact socket. It was like magic.

Today I was working to remove the wheels on my sailboat trailer. With the biggest wrench I had I could lift the tire off the ground, but couldn't break the lug nuts loose. Went to Lowe's to get impact sockets to fit (13/16") and again like magic, in less than 10 sec the impact drill had spun the lug nut off. Can't say enough good about impact drills when you really, really need to get a nut off. And this is a low end Sears battery model that was on sale. Air powered impact drills are much more powerful.

I do use PB Blaster liberally twice in 24 hours, and try to get the nuts with regular wrenches. But when nothing else works, the impact drill does.

Fred W

 

[Timm R Oday25]

While I agree with all that has been post already , I will second the suggestion of cutting the nuts off before pulling the shaft.
The other side of the coin is , why concern yourself as the nuts clearly wont accidently loosen up !
Yeah, I'd cut them off .

 

[jssailem]

found a battery powered impact drill for $70, and got the appropriate impact socket. It was like magic.

SO TRUE. It feels like magic.

 

[jssailem]

cutting the nuts off before pulling the shaft.

This is sensible. Cutting the nuts off (that just has a bad sound to the words. Sounds personal) is not always a cure. It is possible to cut to deeply and then you mess up or destroy the threads on the shaft. (This whole line of the discussion sends shivers down my spine.)

 

[Timm R Oday25]

Perhaps it is my background in industrial maintenance that makes me suggest cutting the nuts.
There are multiple types of nut splitters out there . Most do a fair job . I normally use a 3 inch cutoff wheel for nuts of this size .
Even a small Dremel will work . These will take longer to use . However their small size gives excellent control for a novice.
The key is slowing down and not rushing .
When cutting a nut , you don't cut down to the threads .
A thread file will clean up any threads that may be affected .

 

[testingthewaters91]

Perhaps it is my background in industrial maintenance that makes me suggest cutting the nuts.
There are multiple types of nut splitters out there . Most do a fair job . I normally use a 3 inch cutoff wheel for nuts of this size .
Even a small Dremel will work . These will take longer to use . However their small size gives excellent control for a novice.
The key is slowing down and not rushing .
When cutting a nut , you don't cut down to the threads .
A thread file will clean up any threads that may be affected .

I never really planned to remove the propeller. I just wanted to make the nuts correct in placement. They're backwards now.

 

[LLoyd B]

Just a note of clarification needed as to the correct placement of the lock nut because I am beginning to feel a little bit fat dumb and happy over my believed technical knowledge of stuff. In the past of learning how to do stuff such as don't use pliers on a bolt head and don't stick that screwdriver into electrical wiring. It's always been my understanding to tighten the primary nut down to torque spec and then put a correct sized wrench on the primary nut to keep it from turning and then add a lock nut outside the primary tightened down to an equal or greater amount of torque to keep the primary from loosening. (except for when specifications listed are otherwise )​

 

[testingthewaters91]

Just a note of clarification needed as to the correct placement of the lock nut because I am beginning to feel a little bit fat dumb and happy over my believed technical knowledge of stuff. In the past of learning how to do stuff such as don't use pliers on a bolt head and don't stick that screwdriver into electrical wiring. It's always been my understanding to tighten the primary nut down to torque spec and then put a correct sized wrench on the primary nut to keep it from turning and then add a lock nut outside the primary tightened down to an equal or greater amount of torque to keep the primary from loosening. (except for when specifications listed are otherwise )​

I heard the jam nut goes first. And if not pliers, then what?

 

[pgandw]

Won't be cheap, but correct size wrenches work better than pliers, adjustable wrenches, pipe wrenches, etc, on nuts and bolts. You can even simulate to some degree impact loosening by hitting the wrench end with a mallet.

Fred W

 

[jssailem]

I am not sure that they are Incorrect.
I understand that the larger nut is the primary one. It is tightened to the torque spec, which often means tight (really grunt tight) to most Boat Marine Workers (compared to BMWs, as they charge about the same).

The smaller nut is the locking nut.