New cutlass bearing after 80 engine hours?

[Gary H]

Hi all,

I've just hauled out after just over one year in the water. On the last haul out, 80 engine hours ago, I replaced the cutlass bearing. For about nine months, I could hear the bearing singing at certain RPMs but that finally stopped a couple of months ago.

Now I've got some up and down play in the bearing again. I don't think it can be an engine alignment problem because there's a universal joint between the shaft and the transmission.

It's a Sabre 42 with an external strut, but no room to get the bearing out without pulling the shaft. It's also a very small bearing. 1 1/4 strut with a 1 1/8 shaft.

Ideas?

[model 10]

Seems like it might be that the strut/cutlass bearing and the stuffing box are not in alignment. How is the drip?

[Cheechako]

Hmmm..... Not sure a U joint takes out all the alignment issues. Two would. (think of it this way, if the u joint is at the right angle and you move the engine forward and back.. what happens!)
However, in your boat, the shaft passed thru the packing then on to the strut and cutlass bearing right? That should help to keep the cutlass at least somewhat aligned. Unless you have a wildly out of balance prop, seems like it has to be alignment though. You're saying the total wall thickness (rubber and brass) on your cutlass is only 1/16" per side? really? Is that even possible?
I would disconnect the U joint and with it free, see how the mating surfaces align.
You are aligning two points (cutlass and packing assembly) and adjusting fore and aft with the engine/Ujoint interface, as a third point in space. Getting 3 points aligned is not easy!
???Have I got this right?

[Gary H]

Drip is good. Just a tiny bit when turning with the stuffing box not too hot to hold onto. No drip when not turning.

Prop seems balanced. Was new install 80 hours ago.

Not sure how the stuffing box could be misaligned. It's only connected with hose, but I'm pretty new at this.

Will take a look tomorrow to see if the u joint can be adjusted.

One thought: I installed a line cutter when I replaced the bearing. There's only a small amount of clearance between the aft end of the strut and the cutter. Could this limit the water flow enough to be a problem?

Thanks for the insights.

[Gary H]

Also, will double check the size and post a pic tomorrow. Thanks.

[Gary H]

Double checked the size. It's actually 1 1/4 inch shaft with 1 1/2 inch strut opening.

Help...

[Cheechako]

Checking the alignment is a good starting point. Something is doing it if the Cutlass is worn out already. Are you sure it's worn? there is some play in them usually...
Disconnect the engine coupling and determine if there is proper mating of the coupling surfaces.

[shipleft]

Does the shaft look off-centre when looking at either end of the cutlass or does the rubber in the cutlass show wear on either end. it could be a miss-aligned strut. Up and down movement - there is always a little, because your shaft is supposed to be riding on an thin, entrapped layer of water, not directly on the rubber. With a high speed shaft, a slightly miss-aligned strut and/or a slightly out-of-balance prop will wear that rubber out pretty quick ! As long as some water can move through the bearing when running, I don't think that cutter would create a problem.

[Gary H]

Finally got the shaft pulled. There was play up and down but not side to side. I'm going to install the new bearing and see how things line up.

[BriaF]

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[Cheechako]

Originally Posted by Gary H

Finally got the shaft pulled. There was play up and down but not side to side. I'm going to install the new bearing and see how things line up.

When you get it reassembled, check the mating surfaces at the engine coupling. If it's not a long shaft between the stuffing box and the engine you should be able to check it in the "free state", unsupported, although I assume you will have to hand support the U joint.

[Gary H]

Thanks for all the replies. I think I found the culprit - a low quality, off-brand cutlass bearing. Just installed a new Morse bearing and things line up perfectly. Will splash next week.

[4HMainer]

If you get shaft bearings that are a clearance fit in the P bracket/strut you can have a dry run installation which can show you if the bearing carrier is aligned. Chock shaft and you should be able to insert and turn bearing by hand. Once this is achieved coat in low temp epoxy and re insert.

This is common practice with new bearing materials for water lubed shafts now. The bearing will always wear more in the base as it is effectively dry when it starts and this is when most wear happens.

Clearance for water to exit the bearing for cooling should be no less than 3.00mm 1/8th"

[Cheechako]

I hope you are going to check alignment....