I have discovered that the propeller shaft has worn through the bottom of the bronze stern tube. Somehow the motor has shifted down so far that the shaft has gradually worn through the tube and 1/2 inch into the stern tube flange that is bolted to the outside of the hull. No wonder it was leaking. This appears to me, with my limited knowledge, to be more than alignment. Maybe it is a motor mount issue. The engine is bolted to the top of the mounts. I have purchased a new stern tube the installation of which will require removal of the shaft from the boat. Being the cheap person that I am, I am hoping that when I remove the old stern tube and the cutlass bearing I can either wiggle the shaft past the rudder or remove enough foam from the rudder to get the shaft out. I would appreciate any advice on this problem. I don't know what I am doing with this.
Hunter 34 Stern Tube
- Thread starter Jacques C
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I think you have to remove the P bracket that holds the cutlass bearing. Its held on with 4 bolts and bonded with 5200 so can be difficult to remove as its recessed into the hull.
You should be planning to drop the rudder while the boat is on the hard, removing the prop will more than likely not get the shaft past the rudder and cutting away rudder is not the way to fix your problem. While the rudder is off take the time to repack the gland on the rudder post and not have it leak a week after you re-install the rudder.
Getting the prop strut off is probably not going to be a piece of cake either. It will be through bolted onto the hull and as mentioned in this post access to the nuts on the inside of the hull may be in a very restricted area, once the bolts have been removed applying some heat to the old strut may soften the packing material (probably 5200) and then my suggestion would be to try and apply pressure to the strut to the point where a piece of strong wire or high test fishing line could be worked under a corner of the strut. From this point wrap the two ends of the wire around two pieces of broom stick and work it back and forth under the strut. This will cut through even the 5200 and let the strut come loose. The remaining sealing compound can then be scrapped away before you install the new strut and cutlass bearing.
When you rebed the new strut and bearing make sure to include the backing plates inside the hull when you bolt it all back together.
As to your alignment and motor mount issues, you'll have to check both these items for wear, new mounts may in fact be a good idea if they appear to be worn. Re-alignment will be much easier with new mounts. Repacking your stuffing box will also have to be on your list of to do's with the new strut and cutless bearing in place.
Getting the prop strut off is probably not going to be a piece of cake either. It will be through bolted onto the hull and as mentioned in this post access to the nuts on the inside of the hull may be in a very restricted area, once the bolts have been removed applying some heat to the old strut may soften the packing material (probably 5200) and then my suggestion would be to try and apply pressure to the strut to the point where a piece of strong wire or high test fishing line could be worked under a corner of the strut. From this point wrap the two ends of the wire around two pieces of broom stick and work it back and forth under the strut. This will cut through even the 5200 and let the strut come loose. The remaining sealing compound can then be scrapped away before you install the new strut and cutlass bearing.
When you rebed the new strut and bearing make sure to include the backing plates inside the hull when you bolt it all back together.
As to your alignment and motor mount issues, you'll have to check both these items for wear, new mounts may in fact be a good idea if they appear to be worn. Re-alignment will be much easier with new mounts. Repacking your stuffing box will also have to be on your list of to do's with the new strut and cutless bearing in place.
Jacque...
Haven't done what you intend, but here's some thoughts:
Do drop the rudder to make it easier to remove the shaft with the prop still attached.
With the shaft out, make sure it is "true", and not having a ever-so-slight bend in the shaft log area.
Unless the strut is loose, don't mess with it, but do consider replacing the cutlass bearing while the shaft is out.
If the shaft wore the stern tube ovoid, you may want to re-glass/reinforce that whole area after removing the old stern tube shaft log assembly.
Check all four motor mounts for softness. Replace all four if there's any doubt.
You said the engine was mounted at the top of the mounts. Given that, am trying to figure out how there could have been a misalignment that allowed the shaft to eat up the lower portion of the stern tube. The amount of damage is huge IMHO.
Motor alignment is done with the shaft uncoupled from the trans after the shaft, cutlass bearing and shaft log are all installed and in-place. The coupling plates must be aligned with a feeler gauge wiith no spacing difference top/bottom/left/right. So, having the engine sitting at the top of its mounts doesn't make sense unless the mounts were replaced and the engine wasn't realigned.
The strut would be a pivot point of a degree either way, but it would seem that the cutlass bearing would show some unusual ovaling too, at thefront and back, if the shaft was misaligned low at the stern tube. This seems inconsistant if the engine was at the top of each motor mounting.
Final thought: It sounds like the motor mounts were replaced with the wrong ones and the engine couldn't be raised high enough to get a proper alignment. The ones used apparently didn't have enough thread height to get the engine to the proper height.
Haven't done what you intend, but here's some thoughts:
Do drop the rudder to make it easier to remove the shaft with the prop still attached.
With the shaft out, make sure it is "true", and not having a ever-so-slight bend in the shaft log area.
Unless the strut is loose, don't mess with it, but do consider replacing the cutlass bearing while the shaft is out.
If the shaft wore the stern tube ovoid, you may want to re-glass/reinforce that whole area after removing the old stern tube shaft log assembly.
Check all four motor mounts for softness. Replace all four if there's any doubt.
You said the engine was mounted at the top of the mounts. Given that, am trying to figure out how there could have been a misalignment that allowed the shaft to eat up the lower portion of the stern tube. The amount of damage is huge IMHO.
Motor alignment is done with the shaft uncoupled from the trans after the shaft, cutlass bearing and shaft log are all installed and in-place. The coupling plates must be aligned with a feeler gauge wiith no spacing difference top/bottom/left/right. So, having the engine sitting at the top of its mounts doesn't make sense unless the mounts were replaced and the engine wasn't realigned.
The strut would be a pivot point of a degree either way, but it would seem that the cutlass bearing would show some unusual ovaling too, at thefront and back, if the shaft was misaligned low at the stern tube. This seems inconsistant if the engine was at the top of each motor mounting.
Final thought: It sounds like the motor mounts were replaced with the wrong ones and the engine couldn't be raised high enough to get a proper alignment. The ones used apparently didn't have enough thread height to get the engine to the proper height.
Since you are going to undo the coupling anyway to align, I would pull the prop and lift the engine- 4X4 across the companion way, piece of chain attached to the lifting loops on the motor, and your main-sheet blocks and line. You only need to lift high enough to get the coupling out from the front of the motor. I didn't have to disconnect anything to raise the engine that high.
I doubt that you will have room to slide the shaft past the rudder ( I tried)- I have no idea how you did that with the prop on it Guillaume? and dropping the rudder does not give you much more room. Dropping enough to remove the rudder will probably mean digging a hole to drop it enough to free the top of the shaft. I abandoned that idea when I came upon a piece of cement sidewalk about 8" down.
Cutting a chunk out of the rudder is not the answer and I would not touch the strut- both because I tried that and 5200 IS PERMANENT! Couldn't move the bolts and I think getting it back in exactly the same place could be problematic
I doubt that you will have room to slide the shaft past the rudder ( I tried)- I have no idea how you did that with the prop on it Guillaume? and dropping the rudder does not give you much more room. Dropping enough to remove the rudder will probably mean digging a hole to drop it enough to free the top of the shaft. I abandoned that idea when I came upon a piece of cement sidewalk about 8" down.
Cutting a chunk out of the rudder is not the answer and I would not touch the strut- both because I tried that and 5200 IS PERMANENT! Couldn't move the bolts and I think getting it back in exactly the same place could be problematic
Removing the rudder is a really big job. The boat has to be another 4 foot above ground to get clearance and the steering quadrant is probably corroded tight to the shaft.
Removing the P bracket is relatively easy. Once the bolts are out, put a ratchet strap onto it and the other end up to the toe rail and when tight it will flex enough to get to the 5200 to cut it through.
Realigning the strut is easy. Just bolt it back and check its in line with the centre of the rudder. Then set the engine in line with the shaft. Check again after a couple of weeks of being back in the water as the hull does flex when on the hard.
Removing the P bracket is relatively easy. Once the bolts are out, put a ratchet strap onto it and the other end up to the toe rail and when tight it will flex enough to get to the 5200 to cut it through.
Realigning the strut is easy. Just bolt it back and check its in line with the centre of the rudder. Then set the engine in line with the shaft. Check again after a couple of weeks of being back in the water as the hull does flex when on the hard.
fantastic information Thanks so much. It does sound like the motor mounts were replaced with the wrong ones but I know this boat's history and it has had very little maintenance. Still, that seems to me to be the most likely explanation for problem. The only way to drop the rudder where I am is to have the travel lift pick up the boat. At Grand Lake, Tera Miranda Marina is the only one capable of lifting my boat - a monopoly and they know it and charge accordingly. Is there any chance that the steel L plates that hold the motor mounts could have shifted? They don't look like it. Richard, is it necessary to lift the motor to remove the shaft coupling from the transmission or were you talking about another issue? How do you check the motor mounts for softness? Thanks for your help. This does look like a big big problem to me and the yard workers do not appear to be competent enough to solve it.
Jacques, FYI info I did remove the strut and did not find it particularly difficult. Easily accessed from the stern cabin, there are 2 bolts only. You will need someone under the boat with a large Phillips screw driver (in my case). I forget what the name is (I think it's DeBond or Antibond) but there is a product that mollifies 5200 and makes it a lot easier to remove.WM use to have it. check this site: http://www.marineformula.com.
Re-aligning it as explained in previous post by Hunter Voyager is fairly easy, more so if the bolt holes are not damaged so be careful when removing. I installed a backplate rather than the skimpy little washers that hunter had used. Good luck
Re-aligning it as explained in previous post by Hunter Voyager is fairly easy, more so if the bolt holes are not damaged so be careful when removing. I installed a backplate rather than the skimpy little washers that hunter had used. Good luck
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Jacques- the reason for lifting the motor is to slide the shaft- with the shaft half of the coupling still on - out from under the motor towards the front of the boat. You of course have to remove the prop. When I thnk about it, I believe I removed the shaft half of the coupling before sliding the shaft out- thus not lifting the motor as high
You can "press the shaft half of the coupling off the shaft by undoing the 4 coupling bolts, putting a spacer between the shaft end and the transmission shaft end and putting 4 longer bolts in and tightening them up to press the shaft out. There are more detailed instructions in the forums.
You can "press the shaft half of the coupling off the shaft by undoing the 4 coupling bolts, putting a spacer between the shaft end and the transmission shaft end and putting 4 longer bolts in and tightening them up to press the shaft out. There are more detailed instructions in the forums.
If you are purchasing new mounts be aware that there are different mounts for the forward vs the aft. Be sure to get OEM Yanmar mounts. I think the aftermarket ones do not have different fore/aft.
You may find you can replace the bronze shaft log without removing the shaft. With the coupling disconnected the shaft should slide towards the rudder by 8 inches . This enables you to unbolt the log and slide it off.
When I refurbished my sterngear I put in a new Yanmar shaft coupling and a volvo shaft seal. The standard 1" seal fitted the original bronze shaft log perfectly. This seal holds the shaft central to the log so you can move the engine to centralize it to the shaft coupling.
Then using feeler gauges get the engine square to the new flange to within a few thou.
Tighten the flange to the gearbox then tighten the shaft coupling onto the shaft. The yanmar coupling uses a key align the coupling on the shaft then has bolts through it to rigidly clamp it to the shaft.
The end result on mine is a vibration free installation and a dripless shaft gland and its been trouble free for 6 years now.
When I refurbished my sterngear I put in a new Yanmar shaft coupling and a volvo shaft seal. The standard 1" seal fitted the original bronze shaft log perfectly. This seal holds the shaft central to the log so you can move the engine to centralize it to the shaft coupling.
Then using feeler gauges get the engine square to the new flange to within a few thou.
Tighten the flange to the gearbox then tighten the shaft coupling onto the shaft. The yanmar coupling uses a key align the coupling on the shaft then has bolts through it to rigidly clamp it to the shaft.
The end result on mine is a vibration free installation and a dripless shaft gland and its been trouble free for 6 years now.
Thanks Hunter Voyager. I checked and the shaft without prop has 17" of room before it reaches the rudder. The shaft is about 12" long inside the boat. I have unbolted the coupling from the transmission coupler and removed the stern tube (still around the shaft). Now I need to remove the shaft from it's coupler. Any ideas? The shaft is aligned and turns freely. The photo's are the stern motor mounts and the damaged bronze stern tube.Claude That is a fine looking castle nut you have holding your propeller. Is that another part you had made or can it be bought somewhere? I assume it is bronze.
Jacques
Jacques
It is bronze and I bought it at a prop shop here in town. Check with prop and shaft suppliers in your area.
Jacques,
I have those same after market motor mounts. Have a look at my earlier post and how I was able to shim them up. They work much better when they are mounted lower on that threaded post.
http://forums.hunter.sailboatowners.com/showthread.php?p=735876&highlight=new motor mount
Allan
I have those same after market motor mounts. Have a look at my earlier post and how I was able to shim them up. They work much better when they are mounted lower on that threaded post.
http://forums.hunter.sailboatowners.com/showthread.php?p=735876&highlight=new motor mount
Allan
Sorry Jacques. The shaft log has to be fitted from the outside. I think the only option is to remove the P Bracket as discussed earlier. The shaft can then be removed and a new shaft log fitted.
Looks like you will need packers under the engine mounts. Anything that is solid and stable will do for packers. Just dont use wood. Stainless steel strip would be best. Aluminium would be OK as long as you keep salt water away. Acetal would also be good .
Looks like you will need packers under the engine mounts. Anything that is solid and stable will do for packers. Just dont use wood. Stainless steel strip would be best. Aluminium would be OK as long as you keep salt water away. Acetal would also be good .
Did not read everything but to clarify I did need to remove the shaft strut and the shaft does not need to extend past the rudder this way. The coupling to the engine-end of shaft was fairly easy to remove. I dont remember how mine was made... possibly two set-screw ?
Thanks to all. I am ordering new engine mounts from Yanmar and will have a new cutlass bearing installed. Hopefully that will be the fix. I will be looking for that castle nut. I will try to press out the shaft from it's coupling with a socket spacer and longer bolts connected through the two couplers. I am grateful for the time everyone took to reply.
Jacques
Jacques
Jacques if you cannot find the castle nut, install 2 nuts one after the other and lock them together. Generally one fairly thick the other a little thinner. Do make sure the 2 tightened nuts clear the hole in the shaft for the cutter pin to be installed.
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