Cutless Bearing

[joe_db]

Mine has at least 1/4" play. Is it time to replace?
Also, how much shaft is allowed aft of the bearing?
Thanks

[sastanley]

1/4" ? That seems like a lot to me. I would not want any more than the smallest rattle.

There is some rule of thumb for the amount of shaft you can have hanging back there not including the prop..it might be one shaft diameter. mine is about 3/4" on a 1" shaft.

[JOHN COOKSON]

1\4" play on the cutless bearing seems excessive to me. Here's an article on replacement.

TRUE GRIT

[ILikeRust]

1/4" sounds huge to me. Sure sounds like you need to replace.

Is yours in a strut, or in the deadwood?

[ndutton]

Originally Posted by joe_db

Also, how much shaft is allowed aft of the bearing?

The old rule of thumb was one shaft diameter.

[hanleyclifford]

The cited article says 3/16" but I think that is also too much. Before taking the old bearing out study it carefully. Find out exactly how the shaft has been running. The bearing and shaft have much to tell you about how your engine is mounted and aligned.

[67c&ccorv]

I wouldn't think there would be 1/4" thickness of rubber in the cutlass bearing...

Man, you must have some stuffing box!

[weephee]

I don't mean to hijack this thread but the distance between my prop and the cutlass bearing is at least 6 inches and I believe the set up is original to the boat. If it were the thickness of the shaft, how would you attach a zinc to it. My boat is a full keel columbia 8.3. Maybe that makes the difference??

[ndutton]

Originally Posted by weephee

If it were the thickness of the shaft, how would you attach a zinc to it. My boat is a full keel Columbia 8.3.

Usually the zinc on such an installation is bullet shaped and located on the castle nut. The shaft diameter spacing is not a hard and fast rule, I'm sure there's a wide variety of dimensions out there.

When it comes to prop distance from the bearing (the last support), less is better but there should be enough space for the bearing to pass water.

Somewhat related was the setup I had on my full keel Westsail. I drilled and tapped a 1/2" pipe thread into the bronze shaft log behind the stuffing box and ahead of the bearing. I plumbed a Tee into the cooling water circuit and directed a portion of the water into the forward end of the shaft log forcing water through the bearing under pressure rather than simply immersing it. The system really worked great but when I tested it on the hard I had a bunch of "experts" running around waving their arms and yelling at me that I had a serious water breech in my driveline.

Imagine the puzzled looks and head scratching when I told them no, it's supposed to do that.

[joe_db]

You have 6 inches of shaft hanging free BEHIND the cutless
I have about 2 and am planning to move the engine up and cut down to about 1/2".

Originally Posted by weephee

I don't mean to hijack this thread but the distance between my prop and the cutlass bearing is at least 6 inches and I believe the set up is original to the boat. If it were the thickness of the shaft, how would you attach a zinc to it. My boat is a full keel columbia 8.3. Maybe that makes the difference??

[ILikeRust]

Yeah, I've got something like that too.

Just to be clear, when we're talking about amount of prop shaft behind the cutless, we're really talking about how much prop shaft extends behind the cutless but in front of the prop, yes? Because you need a few inches for the prop to hang on. So we're talking about how much space there is in between the cutless and the forward side (I guess you might consider it the backside) of the prop.

On my boat, there is enough space to attach a zinc to the prop shaft in between the cutless and the prop.

I actually will find out for sure soon - I plan on re-installing the prop shaft this weekend and then dropping the engine back in sometime next week.

[joe_db]

I have 2 inches or maybe 2.5 from the forward end of the prop to the aft end of the cutless. My zinc is forward of the cutless.

Originally Posted by ILikeRust

Yeah, I've got something like that too.

Just to be clear, when we're talking about amount of prop shaft behind the cutless, we're really talking about how much prop shaft extends behind the cutless but in front of the prop, yes? Because you need a few inches for the prop to hang on. So we're talking about how much space there is in between the cutless and the forward side (I guess you might consider it the backside) of the prop.

On my boat, there is enough space to attach a zinc to the prop shaft in between the cutless and the prop.

I actually will find out for sure soon - I plan on re-installing the prop shaft this weekend and then dropping the engine back in sometime next week.

[sastanley]

Here is mine...3/4" inch. sounds like you me and joe are on the same page, bill.

(FYI - this was before shaft/stuffig box/shaft log/cutless work last summer..)