Replacing Cutlass Bearing / Shaft - Problems

[Dfisher]

Ive been chasing a severe vibration problem that doesn't allow my 1983 Hunter 31 to get to full RPM since I bought it and had narrowed it down to the following problems that all added up - worn cutless bearing, slightly bent prop shaft, and the MaxProp folding prop had too much play and was not set to the right angle. I have everything I need but ran into the following problems today:

1) I removed the old cutlass bearing today and when I went to put the new one in I was able to fully insert it into the strut with a couple hits of my palm. I do not feel any play in it but the set screws will be the only thing that holds it in place permanently. One of the existing 5/16 screws stripped out and I plan on drilling / tapping it to 3/8s. Will this be a problem that will require a new strut? I was under the impression that the new bearings needed to be pressed into place.

2) Before fully understanding the MaxProp I ordered the prop shop from the Hunter Store. I provided the measurements of the existing prop shaft before realizing that part of the MaxProp install entails cutting the extra threads off the shaft. The result of this will be that the propeller will sit 7/8" closer to the boat because this shaft is shorter. I wouldn't think this would be a big deal but I though I would run it passed others before re-installing the rudder and putting her back in the water.

Thank you for your input.

 

[seadaddler]

cutlass

I am very sure the cutlass bearing should be very hard to press the bearing after replacing mine on my 2007 H-36 and check how to do it on Main sail's
web site can help you too.
Nick

 

[Allan12210]

My cutless has always inserted with about that same amount of force as well. I stripped out one of my screws about 25 years ago as well and never fixed it. So far, it has never moved in the strut. Maybe that's why there are zincs on one side and the prop on the other to keep it in place. Okay, I know that's not right, but the reality is there isn't that much force operating in that direction. You could take a small center punch (one of those with the spring loaded points) and pop it a couple of times around the front and back of the strut ID. That will knurl it enough to give a bit more holding power. I would not replace the strut.

I think your biggest issue is that slightly bent shaft. If it is indeed, you need to have that checked and fixed/replaced. With significant vibration it won't just be the cutless that wears, but some rather expensive transmission components starting with the oil seal and tail shaft bearings.

Put a Drive Saver, or shaft vibration dampener between the coupling faces behind the engine and it will move your prop back to a more suitable location.

 

[Dfisher]

Thanks Allen. That makes me feel better about that Cutlass and I will move forward with the install tomorrow. I have a new shaft to replace the bent shaft but the issue is that it is 7/8" shorter than the one that came off the boat. I'm wondering if that will cause a problem down the road. The cutless bearing being a little loose may be a blessing in disguise, this way i can get the new shaft through the strut and then slide the bearing in so I don't have to dig a hole to drop the rudder into

My cutless has always inserted with about that same amount of force as well. I stripped out one of my screws about 25 years ago as well and never fixed it. So far, it has never moved in the strut. Maybe that's why there are zincs on one side and the prop on the other to keep it in place. Okay, I know that's not right, but the reality is there isn't that much force operating in that direction. You could take a small center punch (one of those with the spring loaded points) and pop it a couple of times around the front and back of the strut ID. That will knurl it enough to give a bit more holding power. I would not replace the strut.

I think your biggest issue is that slightly bent shaft. If it is indeed, you need to have that checked and fixed/replaced. With significant vibration it won't just be the cutless that wears, but some rather expensive transmission components starting with the oil seal and tail shaft bearings.

Put a Drive Saver, or shaft vibration dampener between the coupling faces behind the engine and it will move your prop back to a more suitable location.

 

[Dfisher]

I just read the last sentence of your post and that should work out well. I think PYI Inc. makes a nice one.

Thanks Allen. That makes me feel better about that Cutlass and I will move forward with the install tomorrow. I have a new shaft to replace the bent shaft but the issue is that it is 7/8" shorter than the one that came off the boat. I'm wondering if that will cause a problem down the road. The cutless bearing being a little loose may be a blessing in disguise, this way i can get the new shaft through the strut and then slide the bearing in so I don't have to dig a hole to drop the rudder into

 

[Allan12210]

Excellent. I think you will be in good shape and the PYI isolator is a good move.

I guess I missed that it was a new shaft that was shorter, not the old one. Sorry about that.

Are your motor mounts good? Sometimes they can contribute to vibration as well. Since you are in a spending mood.........

 

[Dfisher]

I'm hoping the motor mounts are OK. The new shaft and the repair bill for the MaxProp have blown the budget

 

[Slow lane]

You are most likely finished this project by now but you may want to look at a product called bearing retaining compound by loctite.Most bearing suppliers will have it. I often use it for holding bushings and sleeves in place as well as bearings. It's primary use is on worn shafts on large industrial machinery. I always have some with me at work.