Swapping out a jet pump for a prop lower?

[OregonApe]

Long story short, 2001 Mercury XR6 150 20" long shaft on my 25" XL transom. Currently has a jet pump on it so the height difference works because the bottom of the pump is flush with the bottom of the transom. I got myself a used bay kit with a 5" spacer and 5" extensions for the drive and shift shafts. I had to track down a couple of extended bolts but I think I'm ready for install.

I hate the lack of steering at low speeds with the pump. I'm also only fishing lakes and big rivers so I'm not worried about damaging a prop. I actually have the original prop lower that came on this motor though it is missing the water pump (presumably the water pump is in the jet pump at the moment).

I was going to have my outboard guy do the swap but he's busy, a couple hours away, and only open on weekdays which makes it tough to get it to him to work on.

From what I can tell it shouldn't be that difficult to do myself, especially with an extra set of hands around. Still, I would like to get some feedback before I start tearing into things. I'm guessing there is gear oil in the jet pump to drain first. Remove nuts holding the pump onto the driveshaft housing, lower enough to pull the speedo tube, remove the jet pump. Pull water pump from jet pump, rebuild with correct rebuild kit, install on prop lower, grease drive and shift shafts and 5" shaft extensions on the prop lower, make sure it's in neutral, raise into position with enough gap to plug in speedo tube, plug in speedo tube, fit drive and shift shafts into place, hand tighten nuts, torque nuts to spec (50lbs?), fill with gear oil, install prop with hub kit. Original anodes are still on the lower and are brand new.

Anything I'm missing? I had someone tell me that there is a spring or something you have to watch out for but I'm not sure what he meant. Was he talking about the clutch being spring controlled so you have to be careful not to knock it out of neutral?

 

[FuzzyGrub]

OutBoardJets have install instrucrions based on which pump you have: Install Instructions

They send those instructions, even if purchased already assembled from the factory.
You can kind of reverse engineer them.

I assume the lower unit is what was left over from the initial jet install and not something that was purchased to convert the jet. ie you should have all the parts needed.

No gear oil in jet pump. It has a grease fitting instead.

Not sure what you meant by 5" shaft extension. The drive shaft would be one piece and shift shaft should mate up.

The engine waterpump and housing is reused. Some models like Yamaha have a hole drilled into the housing to prevent over cooling the block. Check the instructions for that. If so, you will need new housing.

Find a service manual for your prop motor. It will have all the re-assembly instructions for your specific motor. There are usually specifics relating to the water pump and shift linkage and if it needs to be in forward or reverse. Merc will have schematics for your motor.

The shift cable on a jet is longer than a prop. Since yours sounds like owner installed, maybe there was just an extension that would need to be removed. Look to see if you have all the parts to reattach the shift cable to motor.

FWIW: I have never made the switch, just read about it via the manuals that came with ours.

 

[OregonApe]

OutBoardJets have install instrucrions based on which pump you have: Install Instructions

They send those instructions, even if purchased already assembled from the factory.
You can kind of reverse engineer them.

I assume the lower unit is what was left over from the initial jet install and not something that was purchased to convert the jet. ie you should have all the parts needed.

No gear oil in jet pump. It has a grease fitting instead.

Not sure what you meant by 5" shaft extension. The drive shaft would be one piece and shift shaft should mate up.

The engine waterpump and housing is reused. Some models like Yamaha have a hole drilled into the housing to prevent over cooling the block. Check the instructions for that. If so, you will need new housing.

Find a service manual for your prop motor. It will have all the re-assembly instructions for your specific motor. There are usually specifics relating to the water pump and shift linkage and if it needs to be in forward or reverse. Merc will have schematics for your motor.

The shift cable on a jet is longer than a prop. Since yours sounds like owner installed, maybe there was just an extension that would need to be removed. Look to see if you have all the parts to reattach the shift cable to motor.

FWIW: I have never made the switch, just read about it via the manuals that came with ours.

I believe the lower is the original lower for the motor, but I am completely speculating. Theory #1, original owner of the boat (20' north river mariner) wacked a prop and switched to a jet to avoid making that mistake again. That would explain why there is not currently a prop with the lower. However, that seems unlikely because the motor is a 20" shaft and the transom is 25", so the motor would have been too short for the boat it is on and it would have been tough to wack a prop with it partially behind the transom. Theory #2, the original owner ordered it with a jet pump from the dealer and the dealer swapped out the jet for the original lower and gave him some credit for keeping the prop that came on it. That would explain why it has no prop and why the lower looks brand new other some dirt from sitting for 20 years. The original owner is deceased so I'm unlikely to ever know.

The 5" shaft extension are because I had to get a Bay MFG 5" spacer kit to take it from a long shaft to a XL shaft to get the water intakes below the bottom of my transom.

From what I have read, neutral is where I want to be for install.

In this case I believe it is a shift shaft (like a miniature version of the drive shaft) instead of a cable. I also have a 5" extension for it because the Bay kit spacer adds 5".