prop shaft replacement

[jsproline]

I have a 1988 sport craft 270 hardtop. It has a straight drive vortec 350 borg warner velvet drive. The prop shaft was in need of replacement so I have a new one as well as a new coupler
a new cutlass bearing. I also upgraded to a last drop prop shaft seal it has a cutlass bearing in it. I had the prop done too.
All the new parts are in but it the prop shaft seems a bit tight. I can spin it with my hands but it takes some effort. Is this too tight? I know that the water is the lubricant for the bearings but I am afraid this is not in correctly. I do not want to destroy all these new parts by running it this way what can I do? The prop shaft wants to sit lower in the shaft log than the new seal will let it. I think the old seal will cause it to bind as well. The shaft is now centered in the log. If i let the shaft sit as it wants to then it will almost touch the bottom of the log.

 

[Grub54891]

Re: prop shaft replacement

I use a squirt bottle with soapy water to lube em up if need be.The shaft should be centerd in the cutless,if not you have an alignment issue. Why was the shaft replaced to begin with? You check alignment at the coupler,preferaby when the boat is in the water in its natural " relaxed" state. They do flex a tad when on the trailer,or blocking. If ya just cant get perfect alignment at the coupler by raising/lowering the motor mount adjustments,I've seen a couple that had to have the strut removed,shimmed properly,then re-bedded.
Let us know what ya figure out.
Grub

 

[jsproline]

Re: prop shaft replacement

soapy water seems to help but i think it can be a better fit. I think the cutlass will have to be adjusted. The shaft was removed due to corrosion and a deep cut where the shaft packing was over tight. i hope this shaft will last as long as the first one.

 

[alldodge]

Re: prop shaft replacement

I have a 1988 sport craft 270 hardtop. It has a straight drive vortec 350 borg warner velvet drive. The prop shaft was in need of replacement so I have a new one as well as a new coupler
a new cutlass bearing. I also upgraded to a last drop prop shaft seal it has a cutlass bearing in it. I had the prop done too.
All the new parts are in but it the prop shaft seems a bit tight. I can spin it with my hands but it takes some effort. Is this too tight? I know that the water is the lubricant for the bearings but I am afraid this is not in correctly. I do not want to destroy all these new parts by running it this way what can I do? The prop shaft wants to sit lower in the shaft log than the new seal will let it. I think the old seal will cause it to bind as well. The shaft is now centered in the log. If i let the shaft sit as it wants to then it will almost touch the bottom of the log.

The prop shaft being tight when turning with your hand is normal. The cutlass bearing is water lubricated and even in the water should drag a bit. Your shaft should be in the center of the shaft log or real close to it. With the prop shaft installed, no bolts in the coupler, how far off are the faces of the coupler (up, down, left, right)?

 

[jsproline]

Re: prop shaft replacement

Not sure what you mean about "how far off are the faces of the coupler" Currently the engine and trans are up and out of the way. I had to do this to take the old shaft out and put the new shaft in. The shaft almost wants to touch the bottom of the shaft log it it sits in the cutlass and I do not install the shaft seal. The shaft seal is a last drop and it has its own bearing in it too. When i install the seal the shaft is centered in the log but it also feels like it is binding. I have not tried to align the engine yet. I have not been able to do anything else with the temps we have had. When i got this boat I thought it would be an easy fix given the design of the straight shaft and velvet drive. It has been interesting and thats what I get for thinking.

 

[alldodge]

Re: prop shaft replacement

Not sure what you mean about "how far off are the faces of the coupler" Currently the engine and trans are up and out of the way. I had to do this to take the old shaft out and put the new shaft in. The shaft almost wants to touch the bottom of the shaft log it it sits in the cutlass and I do not install the shaft seal. The shaft seal is a last drop and it has its own bearing in it too. When i install the seal the shaft is centered in the log but it also feels like it is binding. I have not tried to align the engine yet. I have not been able to do anything else with the temps we have had. When i got this boat I thought it would be an easy fix given the design of the straight shaft and velvet drive. It has been interesting and thats what I get for thinking.

Know what you mean about the temps, being waiting for warmer temps to get the rest of engine out of my dozer.

The shaft should sit easy in the center of the shaft log and there should be next to no difference in tightness with or without the log bearing being installed. Does it look like the strut may be causing the alignment variation? As before the cutlass bearing will drag when trying to turn it by hand but not so much as to be very difficult. There should be around .003 gap for the water to flow around the shaft. If it appears tighter check to make sure you have the right cutlass for the shaft, you proably do.

 

[K-2]

Re: prop shaft replacement

I have a 1988 sport craft 270 hardtop. It has a straight drive vortec 350 borg warner velvet drive. The prop shaft was in need of replacement so I have a new one as well as a new coupler
a new cutlass bearing. I also upgraded to a last drop prop shaft seal it has a cutlass bearing in it. I had the prop done too.
All the new parts are in but it the prop shaft seems a bit tight. I can spin it with my hands but it takes some effort. Is this too tight? I know that the water is the lubricant for the bearings but I am afraid this is not in correctly. I do not want to destroy all these new parts by running it this way what can I do? The prop shaft wants to sit lower in the shaft log than the new seal will let it. I think the old seal will cause it to bind as well. The shaft is now centered in the log. If i let the shaft sit as it wants to then it will almost touch the bottom of the log.

I think I get what you are saying. The shaft with the coupling on it is too much weight for the shaft seal to hold centered in the seal and shaft tube. And now you need to install the engine,,but how you going to align the engine to a shaft/coupling that is "sagging" ?
Is this your problem?

 

[Ned L]

Re: prop shaft replacement

When aligning the engine you should use a spring scale to life up on the coupling end of the shaft with 1/2 of the weight of the shaft. This is to remove the natural 'sag' in the shaft before coupling it to the engine. Also, the coupling faces should have a max of .003" clearance between them at any point prior to bolting them up to each other.