Primary shaft bearing RR while afloat?

I have a 1991 500B S/N 4100130727 with a DP-C drive S/N 3102121005 installed in a 75? houseboat permanently moored on the water. The primary shaft bearings in the flywheel housing are howling at me and I?m going to have to replace them. Can this be done with the boat still in the water?

I have a removable hatch directly over the engine and about 10? of forward clearance. I have an engine hoist and have read the ?Instructions for replacing the primary shaft bearing? sticky. It looks like I have the 13? cover with the dual bearings, as I have a grease fitting installed on top.

My biggest concerns are alignment after reinstall, and whether the coupling on the drive side will stay centered after the engine is removed so that they will slide together again during reinstall. I?ve read the thread on alignment, but I?m hoping that 21 years of operation shows the existing alignment is okay. The hull and stringers are aluminum.

I have replaced the gimbal bearing on a Mercruiser Alpha One Gen II several years ago, but this was on dry land and required the alignment tool and a drive removal. The Volvo setup looks much different.

The drives were serviced 3 years ago in a boatyard; new boots, repacked trim cyl, gear oil, props,etc. Pulling the boat out of the water would be an expensive ordeal and the engine would still have to be pulled to get the housing off to replace the bearings. The water barrel trick on the front deck probably won?t work on a 75 footer.

Is there a trick to holding the drive side coupler in place? Thanks. BTW, Don, I read the EF installation manual from another thread. You wouldn?t happen to have one for the earlier engines, would you? It might help

Re: Primary shaft bearing RR while afloat?

If those bearing are howling at you, then you probably have water in the bellows. There is no possible way to replace those bearings with the boat in the water. You must remove the upper gear box, and the flywheel housing from the transom shield to access the snap rings, seals and bearings.

Re: Primary shaft bearing RR while afloat?

I don't think you can do this without sinking the boat. I wouldn't try it on my boat that's for sure. It really depends on the freeboard of your boat in the back...mine is tail heavy and this stuff is under water. You have to pull the transmission on the drive, or the drive itself to get to the doughnut bolts (from the outside), cause I think it's necessary to remove the flywheel cover to get to the 2 bearings.

If this is a AQ style drive (Which I'M 99% that the DPs are), then whatever decision you make on pulling the boat out, the alignment on these things is easy. Once you install the engine, and have the doughnut bolts done up loosely on the outside (Drive off or transmission removed) you modify the engine placement (Usually slots on the front engine mount lag bolt connections, and the front mount nuts for raise/lower). On the flywheel cover there are 3 'bosses', which are like 1/2 inch rectangular protrusions on the flywheel cover. You will find them at 12, 3 and 9 o'clock on the flywheel cover. You make sure these have the same gap (within a small error) to the transom fitting and that's it. There is no gimbal style alignment like on a merc or a volvo SX.

For what it's worth, the original tool for doing this was a notched 'wedge'. I just used a regular old wood wedge. The idea is that you slide in the wedge in the first gap, then draw a line where it stops going in. Do the same on the other two gaps...does it go in the same distance? If not, reallign the engine and try again. They just all have to be nearly the same.


Chay

Re: Primary shaft bearing RR while afloat?

Don S said:

If those bearing are howling at you, then you probably have water in the bellows. There is no possible way to replace those bearings with the boat in the water. You must remove the upper gear box, and the flywheel housing from the transom shield to access the snap rings, seals and bearings.

Click to expand...

Before I bought the boat, there was some seepage out of the weep hole in the bottom of the flywheel housing. That's why it was taken to a boatyard for drive work prior to transport to this lake. The mechanic was supposed to check the bearings for possible water damage, but apparently only check the drive side components. At the time, I only knew Mercruiser and assumed (yeah, I know...) that the "gimble bearing" would be checked. Now I know that he couldn't have checked the primary shaft bearings, and didn't even grease them (nothin on the zerk but paint)

The water problem is fixed. Now I have a bearing talking to me and I need to listen before it starts yelling...

If I understand you correctly, the flywheel housing is attached to the transom shield with fasteners or snap rings that are only accessible from outside the hull, once the drive is removed?

Re: Primary shaft bearing RR while afloat?

Glastron_V210 said:

I don't think you can do this without sinking the boat. I wouldn't try it on my boat that's for sure. It really depends on the freeboard of your boat in the back...mine is tail heavy and this stuff is under water. You have to pull the transmission on the drive, or the drive itself to get to the doughnut bolts (from the outside), cause I think it's necessary to remove the flywheel cover to get to the 2 bearings.

If this is a AQ style drive (Which I'M 99% that the DPs are), then whatever decision you make on pulling the boat out, the alignment on these things is easy. Once you install the engine, and have the doughnut bolts done up loosely on the outside (Drive off or transmission removed) you modify the engine placement (Usually slots on the front engine mount lag bolt connections, and the front mount nuts for raise/lower). On the flywheel cover there are 3 'bosses', which are like 1/2 inch rectangular protrusions on the flywheel cover. You will find them at 12, 3 and 9 o'clock on the flywheel cover. You make sure these have the same gap (within a small error) to the transom fitting and that's it. There is no gimbal style alignment like on a merc or a volvo SX.

For what it's worth, the original tool for doing this was a notched 'wedge'. I just used a regular old wood wedge. The idea is that you slide in the wedge in the first gap, then draw a line where it stops going in. Do the same on the other two gaps...does it go in the same distance? If not, reallign the engine and try again. They just all have to be nearly the same.


Chay

Click to expand...

Thanks, Chay. I thought it might be possible since a friend on this dock with a Volvo 4 banger and SP drive threw a rod last year and had to replace the engine. He pulled the engine with the boat still in the water and dropped in a new one. I should have paid closer attention. His boat is few years older, and his engine and drive are different, but I was hoping Volvo's design philosophy might be similar, letting me remove and reinstall my engine while still afloat. Oh, well.

Re: Primary shaft bearing RR while afloat?

You can change an engine with the boat in the water, you just don't take the flywheel housing (PDS housing) out of the boat.

If I understand you correctly, the flywheel housing is attached to the transom shield with fasteners or snap rings that are only accessible from outside the hull, once the drive is removed?

Click to expand...

The snap rings are in the FWH (Flywheel housing) holding the shaft in. The FWH is held onto the transom shield by a clamp ring and 6 bolts. You have to remove the upper gear box from the drive, remove the 6 bolts and then pull the engine out of boat with the fwh still on the engine. This leaves about a 10" hole in the transom.

Here is a .pdf file from a diesel that shows how the housing fits in the transom shield.

View attachment Install Manual Aquamatic Engines 31.pdf

PS, Yes, you do have the 2 bearing housing.

Re: Primary shaft bearing RR while afloat?

Thanks Don. Just what I needed, but not what I wanted to hear. I'll have to figure out a way to get the transom out of the water, then. Thanks also for the .pdf. Looks like I'm going to have some fun...

I really appreciate you sharing your knowledge and time with folks like me. Makes all the difference. -Rick

Re: Primary shaft bearing RR while afloat?

Don, can you recommend the grease you use to pack these bearings? Thanks. -Rick