bents prop shaft?

[admorton]

I just bought a 28.5. Nice boat! Previous owner says that it has a bent prop shaft. It does have a vibration at low rpm when in gear, but seems to me that it would be much worse with a bent shaft. Are there other things that could cause vibration? Anybody out there that would be interested in repairing my problem in or around Hot Springs, AR?

 

[woodster]

Take the shaft out and take it to a machine shop and have it checked some times they can straighten them if it is to bad to straighten then replace it and move on. Also check the cut less bearing may need replacing too

 

[admorton]

thanks Woody. How hard is it to pull the shaft out?

 

[Sailor_Jeff]

thanks Woody. How hard is it to pull the shaft out?

Is the boat out of the water or in the water? If it is in, can you get it lifted out and put on a hard stand?

If it is a bent shaft, it can / will tear up your packing and this could lead to an ugly leak. Water could come in faster than you can pump it out.

Other things that cause vibrations, fouled prop with a piece of line or trash, like an old Walmart bag. Also a broken or cracked or nicked prop, too big a shaft zink, and there are other things. Also if the strut is excessively worn, stern bearing or shaft log is excessively worn. Not to mention worn shaft.

Good news, all these parts are available from Hunter. (Hunter owners parts). Stern bearing, shaft, shaft log, strut and bronze prop. But you need to get the boat on a hard stand and inspect it. Or, hire an experienced marine surveyor to look at it with you. You can hire them by the hour to look with you.

Nope, most of the time, none if it is too hard to change on a stand on the land.

 

[admorton]

Boat is in water now, but I can get it on a trailer. There is no leak at packing, which is another reason why I doubt the shaft is bent. I think I will have a diver look at before I pull it out.

 

[Nelsonhow]

Might also be a bad motor mount

 

[woodster]

thanks Woody. How hard is it to pull the shaft out?

it can go from very well to why did i start this.......if you have a split coupling it will make things very easy ....but if you have a press fit coupling it can involve as much work as lifting the engine off the bead in order to get the shaft out via sliding it under the lifted engine.... and this is from one razorback(once removed lol) to another

 

[admorton]

Woody, how do I tell if it's a split coupling or press fit?

 

[woodster]

if it is a split coupling it will have a split running the same direction as the shaft and have bolts going across the shaft perpendicular to the shaft like this one... https://www.google.com/search?q=mar...u&source=univ&sa=X&ei=5mVKVcr9DozvoATj74HoDQ&

 

[admorton]

Woody, Thanks for the feedback on pulling my shaft. I appreciate all the photos you attached and I think I have something similar to at least on of them. I finally got to my boat and took a phoho. Assuming I did my attachment correctly, it should be a photo attached here.

Also, among the many things the previous owner left for me, I found something that looks like one of your photo, a flexible shaft connection?? Can I use this???

Thanks again for your help!!

Dean

 

[woodster]

Woody, Thanks for the feedback on pulling my shaft. I appreciate all the photos you attached and I think I have something similar to at least on of them. I finally got to my boat and took a phoho. Assuming I did my attachment correctly, it should be a photo attached here. View attachment 88181

Also, among the many things the previous owner left for me, I found something that looks like one of your photo, a flexible shaft connection?? Can I use this???View attachment 88182

Thanks again for your help!!

Dean

that thing is ok i guess..... a lot of people use them..... but i feel that if you install everything correctly then it is not needed...i am sure that i will excite some response on my statement ...and i would like to hear/read the arguments for it

 

[Nelsonhow]

It's like pealing an onion.....

To pull the shaft.....
1) liberally soak the all bolts with PB Blaster 1 to 2 tines a day for several days prior.
Also soak where the coupling ant shaft meet. The square set bolts too!
2) remove the bolts in the coupling and the square shaft bolts. A plumbers torch can help
3) slide the shaft back and put a small socket between the flanges and using slightly longer bolts and re tighten. This should force the shaft out of the back of the coupling.

Again a little heat farm a torch can help. Keep water near in case and tighten the bolts evenly. Don't crank away on the bolts or you'll bend the coupling flanges. A little gentle tapping with a small hammer also help the PB blaster get in to do its work

4) once the shaft is free from the coupling slide it back it. (Note that the boat needs to be out of the water.

5) Odds are is that the shaft with the prop on will not clear the rudder and you"ll have to pull the prop. Some times even with the prop off the shaft still will not clear the rudder and you have to drop the rudder. If you need to do this you can either drop it while in the water, drop it while it in the lift sling , have the yard lift the boat or dig a hole under the rudder while in the yard. I've always dug the hole. If you drop the rudder you can usually leave the prop on and the shop can pull the prop for you. If you pull the shaft it's a good time to replace the cutlass bearing..

 

[Dan_Y]

Re: It's like pealing an onion.....

We had to drop the rudder on our H30 to pull the shaft. Have you tried to replace the packing yet? It would seem to be a difficult job with so little clearance. Look into at least new hose (hopefully a tad shorter than what's installed now) and use new clamps. New cutlasses bearing is a good recommendation as is having the prop inspected and balanced. Really made our boat run smoother.

 

[Nelsonhow]

Try this....

With a packing removal tool that looks like a corkscrew on a flexible T handle and an assortment of dental picks and a young contortionist it's not to difficult. In the past I've even used a very small long screw to insert into the packing and pulled the packing out with a player. Once you get it started us comes right out......

Once you get the old out and get new the correct diameter. I wrap about a foot of the packing on the shaft outside under the boat and cut diagonally across the top. This gives me about 4 separate rings. You fit them int the packing (usually 3 of them with an extra or 2) into the packing being careful to offset the joint in each ring. I replace the lacking every 2 to 3 years....

 

[admorton]

With a packing removal tool that looks like a corkscrew on a flexible T handle and an assortment of dental picks and a young contortionist it's not to difficult. In the past I've even used a very small long screw to insert into the packing and pulled the packing out with a player. Once you get it started us comes right out......

Once you get the old out and get new the correct diameter. I wrap about a foot of the packing on the shaft outside under the boat and cut diagonally across the top. This gives me about 4 separate rings. You fit them int the packing (usually 3 of them with an extra or 2) into the packing being careful to offset the joint in each ring. I replace the lacking every 2 to 3 years....

Wow, this all sounds pretty intimidating to a guy who has sailed a 23' boat with an outboard for the last 35 years. Are you close to Arkansas and could I talk you into a trip over to help me? HA HA!

Assuming this is not as bad as it sounds from all the comments, and from visual inspection in the water the shaft does not appear to be bent and bearings are not loose, could I assume the prop is the problem and needs to be balanced? Can the prop be removed with the boat in the water, assuming scuba diver? Am I going to find the prop really stuck and hard to get off?

Sorry for all the dumb questions. I really appreciate the comments so far.

 

[Nelsonhow]

Check the easy cheap stuff first.

Before you go in for the big stuff do the simple cheap things.

1)rotate the shaft by hand and see if is moves out of plane (side to side). You'll probable see if there is a bend.... My bet is it's fine
2) dive under boat with a mask and snorkel and look at prop. Does it appear bent. A chip in one of the blades? Is it a folding prop. If so do the blades unfold easily? A big chip or bent blade calls for removing the prop. Which can be done in the water by a diver who has a prop bulkier. But it might be easier to short haul the boat....a rope wrapped in the blades will do it. Look behind the prop too. You can pick up fishing or other line. If there's a wrap a sharp knife an a player can usually get it off.
3) rope or barnacles on the prop or shaft.....scrape the off with a flexible putty knife. Hint wear work gloves. I used the orange nylon gloves with the palms and fingers that I get from Home Depot 6 pairs for about $8 bucks on sale. barnacles are SHARP! Scrape all the way back to the hull. I do the a few times a season while on my mooring.
4) check the Zinc on the shaft. Is it all there and evenly eroded. If not replace it...easy to do in the water with a mask and snorkel
5) Wiggle the strut. Is it loose. If you may be able to tighten it from inside the boat. But my bet is is fine too.
6) check the cutlass bearing by jiggling the shaft it should not have much play. If there is a lot it's worn and should be replaced. But usually it won't cause knocking even it it a worn...

 

[kito]

Might also be a bad motor mount

I was thinking that too but he says "when in gear". So I'm guess he has no vibration problem when in neutral. I replaced all 4 on mine but it was shaking badly in neutral at low rpms. Kind of smoothed out at higher rpms.

 

[Warren Milberg]

Let me ask the obvious: why would the PO tell you the shaft is bent if it is not? Ask him how the shaft got bent in the first place.

FWIW, I simply dropped the strut rather than remove the prop (which was frozen in place) in order to remove the shaft from the boat without removing the prop or the rudder. I did this when I replace the cutless bearing a few years ago.

 

[admorton]

Let me ask the obvious: why would the PO tell you the shaft is bent if it is not? Ask him how the shaft got bent in the first place.

FWIW, I simply dropped the strut rather than remove the prop (which was frozen in place) in order to remove the shaft from the boat without removing the prop or the rudder. I did this when I replace the cutless bearing a few years ago.

I asked but never got a good answer. Had a big rope wrapped around the shaft that he had to cut off. Seems to me that would have seen any damage but didn't say he did.

 

[admorton]

Before you go in for the big stuff do the simple cheap things.

1)rotate the shaft by hand and see if is moves out of plane (side to side). You'll probable see if there is a bend.... My bet is it's fine
2) dive under boat with a mask and snorkel and look at prop. Does it appear bent. A chip in one of the blades? Is it a folding prop. If so do the blades unfold easily? A big chip or bent blade calls for removing the prop. Which can be done in the water by a diver who has a prop bulkier. But it might be easier to short haul the boat....a rope wrapped in the blades will do it. Look behind the prop too. You can pick up fishing or other line. If there's a wrap a sharp knife an a player can usually get it off.
3) rope or barnacles on the prop or shaft.....scrape the off with a flexible putty knife. Hint wear work gloves. I used the orange nylon gloves with the palms and fingers that I get from Home Depot 6 pairs for about $8 bucks on sale. barnacles are SHARP! Scrape all the way back to the hull. I do the a few times a season while on my mooring.
4) check the Zinc on the shaft. Is it all there and evenly eroded. If not replace it...easy to do in the water with a mask and snorkel
5) Wiggle the strut. Is it loose. If you may be able to tighten it from inside the boat. But my bet is is fine too.
6) check the cutlass bearing by jiggling the shaft it should not have much play. If there is a lot it's worn and should be replaced. But usually it won't cause knocking even it it a worn...

Still thinking about my problem, haven't pulled the boat and water is too murky to see anything underwater right now. I did try to evaluate the magnitude of the vibration, not know how much is too much. It definitely is felt in the feet when running in gear. Seems to be more a lower RPM and lessens when at 2000 RPM. I took a video when running at 2000 in gear. I would appreciate anyone's comments.