Pontoon Boat & Deck Boat Forum

Rebuilding a pontoon. Boat has 3.0L Merc I/O motor with a cracked block. I am putting in a new 3.0l motor. I am not a mechanic but am paying someone to do this work. I have a few questions if anyone knows the answers. Once the old motor is pulled and the new one is put in does the lower unit need to be pulled to align it up or can that be done when putting the motor in without pulling the lower unit? If the lower unit has to be pulled to align is this easier to replace the bellows/gimble bering and other related parts while it is off the boat. I guess I asking is the point where the lower unit comes off the transom the same place where the access to the bellows is located or is that a separate area on the lower unit? Thanks.

Depending on how much room you have forward of the motor to slip it off you should be able to do it without removing the outdrive. A friend replaced some type of shear bushing that goes between the outdrives and engines on his houseboat with a 4x4, 2x8, a come along and some wrenches. It's actually fairly straight forward to take that 3.0 out and swap it. If you do have to pull the outdrive then you can check the gimbal bearing but I would for sure replace the bellows which can be a chore in and of itself.

I would say that yes, the drive assembly will need to be pulled and the engine aligned. I did this numerous times when I worked at a Mercury Shop. It may also need to have the alignment checked at the 10 hour service.

The procedure is to remove the drive, and insert a special tool into the engine coupler through the drive transition thrust bearing. The engine mounts are then adjusted until the tool (below) can be inserted and removed without any resistance.

If the alignment is even a little off, you WILL fry the thrust bearing and probably damage other very expensive parts.

BoatCop wrote:I would say that yes, the drive assembly will need to be pulled and the engine aligned. I did this numerous times when I worked at a Mercury Shop. It may also need to have the alignment checked at the 10 hour service.

The procedure is to remove the drive, and insert a special tool into the engine coupler through the drive transition thrust bearing. The engine mounts are then adjusted until the tool (below) can be inserted and removed without any resistance.

If the alignment is even a little off, you WILL fry the thrust bearing and probably damage other very expensive parts.

The thrust bearing...that's what I was referring to above that had to be replaced. Maybe my friend got lucky on his houseboat but he's put a few hundred hours on the motors since pulling and reinstalling without any issues and he didn't pull the drives. The main reason is that it's a little under $2000 each time you have the boat pulled to do any work on it and it's an older houseboat...still nice but that adds up quick. We have gotten pretty creative on fixing things in the outdrive in the water. Some clip came off of the outrdrives that holds the shifter and he had just had the outdrives rebuilt so we were able to get it back on miraculously with some trim and shallow water.

The drive needs to be pulled, its the first thing I pull when removing engine. I dont know how you could even consider pulling engine without pulling the drive. Also, alignment has to be done with drive removed. JT