Propshaft Alignment

[AaronJ]

Hey, I have a Hunter 30 with Yanmar 2gm20f. I'm trying to align the engine to the propshaft. I can move the shaft up and down about 2-3 inches. Is that normal? Also, I'm having a hard time sliding it back away from the engine. It seems to be stuck in place, although it spins. Any comments?

Thanks,
Aaron

[doug86]

Perhaps look for some help from someone who has experience with alignment to show you how. Engine alignment is pretty critical, and not always intuitive (sometimes left is right and up is down). It's all too easy to do it wrong, and that usually ends up with a broken shaft.
The 2-3" of movement may indicate the need to replace your cutless bearing, which should be done before attempting to align the engine. Have you determined if the bearing is good?

[scubasteve]

It would be a good idea to check/replace the cutlass bearing before you begin. Engine alignment is important to eliminate excess wear of your transmission and bearings.

I have a set of instructions in a pdf file format that explains the process. Let me know if you're interested and I can email it to you.

[delmarrey]

Some movement up/down is OK at the motor as long as the shaft is centered in the shaft log, which you can only tell if the stuffing box is removed. If your packing is in place then moving the shaft in/out could be a problem, if the packing has worn a grove in the shaft. The packing is acting as a retainer.

The cutlass bearing has a little tolerance being that far away.

[senormechanico]

I expect Gord here any minute. CutlEss bearings are so called because they were designed to not get cut by debris. At least that's what I heard many years ago.
An internet search gets lots of hits both ways.

[SkiprJohn]

Moving the shaft up and down 2 to 3 inches is scary! I'd really check out the stuffing box to see why there is so much play.
regards,

[AaronJ]

I forgot to mention that my stuffing box is a PSS dripless. I don't think there is anything within it to hold it rigidly in place.

[Chief Engineer]

Do not try to align the engine...on the hard....the boat needs to be in the water

[FSMike]

Originally Posted by senormechanico

I CutlEss bearings are so called because they were designed to not get cut by debris. At least that's what I heard many years ago..

Actually it's "cutlass" bearing.

[Chief Engineer]

Cutless is a trademark for Johnson-Duramax

[scubasteve]

Originally Posted by Chief Engineer

Do not try to align the engine...on the hard....the boat needs to be in the water

This is correct, fiberglass hulls flex and the alignment will change.

[FSMike]

Originally Posted by Chief Engineer

Cutless is a trademark for Johnson-Duramax

Oh. Didn't know that, Chief (and Senor). Doubtless one of many cutlass bearings.

[delmarrey]

Originally Posted by Chief Engineer

Cutless is a trademark for Johnson-Duramax

Obviously some vendors advertise wrong. Some times trade marks spell things wrong so it doesn't violate other patents.

CUTLASS BEARING
Cutlass Bearings: Deep Blue Yacht Supply
Cutlass Bearing - Bloater
Fantasia 35 Mk II Cutlass Bearing Replacement
Duramax Marine Cutlass Bearings
cutlass bearing exporter - cutlass bearing manufacturers, cutlass bearing exporters, cutlass bearing factories, cutlass bearing suppliers, China cutlass bearing
Ships Store Cutlass Bearings Torresen

Even a surveyor calls it a CUTLASS bearing. Marine Engines : Drive System Alignment by David Pascoe, Marine Surveyor (under 'general rule')


And on and on! One can find the spelling the other way just as many times so I'm not going to bother either way, anymore.

Peace!

[Laidback]

Originally Posted by AaronJ

Hey, I have a Hunter 30 with Yanmar 2gm20f. I'm trying to align the engine to the propshaft. I can move the shaft up and down about 2-3 inches. Is that normal? Also, I'm having a hard time sliding it back away from the engine. It seems to be stuck in place, although it spins. Any comments?

Thanks,
Aaron

Hello Aaron,
If you can move the propshaft 2 <> 3 inches - then it appears that you have a problem with the Cutl*ss bearing and/or the "P" bracket. Below is a photo of a Hunter 30 out of the water. Note it has a "P" bracket which holds the shaft in position OUTSIDE the hull, while the Cutlass holds the shaft in position inside the hull.
When the "P" bracket and the Cutlass are lined up, the propshaft can be inserted in both with only enough movement in any direction to allow the shaft to move freely. Once this operation is completed then the stuffing box is adjusted. Then the boat is returned to the water, in order to align the gearbox output flange with the propshaft coupling. Maximum clearance in any direction between flange and coupling is 1/3,000"

[Laidback]

Aaron, forgot to add:- that the reason you cannot move the shaft >> aft, could be because between the cutlass and the "P" bracket one normally has a Zinc anode attached to the shaft, which prevents the shaft moving astern.
Richard