Failed drive shaft

[DougsMessyGarage]

I finally got the pontoon with the Force 120 in the water for a lake test. Couple of minor issues that were easily dealt with and one major failure I need some advice on.

The main drive shaft piled up and sheared off at the the upper bearing of the lower unit. I have the prop shaft assembly pulled and everything there looks like new inside so I figure the lower unit should be salvageable but I need to get the pinion nut off the shaft to get the rest of the disassembly done. Since the input is no longer attached to the pinion gear, how do I hold the drive shaft solidly enough to break the pinion nut free?

The break occurred halfway through the top bearing of of the lower unit. I was thinking of trying to weld a nut to the top of the lower part of the shaft and putting a socket on the nut. The some heat on the pinon nut and hopefully get it loose.

Anyone have a better suggestion?

 

[puffitu]

I do not have any better ideas as to how to get you shaft free but I can tell you that I have a great amount of parts for 1990 120hp including the shaft and adapter. You did not specify what year motor you had unless I missed it somewhere . You can pm me for more info if you like

 

[DougsMessyGarage]

I do not have any better ideas as to how to get you shaft free but I can tell you that I have a great amount of parts for 1990 120hp including the shaft and adapter. You did not specify what year motor you had unless I missed it somewhere . You can pm me for more info if you like

You are correct, I missed adding the model year. Mine is a 1992.

 

[pnwboat]

If you can get an air operated inpact tool, it'll probably get it off without having to hold anything in place.

 

[jerryjerry05]

How's he gonna get the or any tool into the lower unit to undo the pinion nut?
The only tool that fits in there is a 7/8 wrench.
Drill out the shaft and use a BIG easy out?? along with the 7/8 wrench.
No way to get heat in there either.

 

[DougsMessyGarage]

Hey guys, I was able to get the drive shaft out of my gearbox using the easy-out trick. Aside from the piled up top bearing, everything else looks pretty decent.

I have hit a small snag though. I purchased and new old stock, sealed in the bag, FK1203-1 seal kit with the intent of replacing all of the seals during reassembly. I looked at the seals that came with the kit and they looked a bit different than what was in the spool but appeared to be the same size. When I extracted the original prop shaft seals (slightly damaging the outer seal in the process) and went to re-install the new ones, the new ones are about 1/32" larger than original. The inner seal was included with the FK1203-1 kit and I have installed it but I do not have a like-for-like replacement for the outer seal.

According to all of the part number listing I have found online, the FK1203-1 is the seal kit I need but the spool outer seal doesn't seem to come in the kit. Were there multiple seal kits available at one time for the '92 Force 120hp?

Thanks for any guidance you can give.

 

[puffitu]

Hey guys, I was able to get the drive shaft out of my gearbox using the easy-out trick. Aside from the piled up top bearing, everything else looks pretty decent.

I have hit a small snag though. I purchased and new old stock, sealed in the bag, FK1203-1 seal kit with the intent of replacing all of the seals during reassembly. I looked at the seals that came with the kit and they looked a bit different than what was in the spool but appeared to be the same size. When I extracted the original prop shaft seals (slightly damaging the outer seal in the process) and went to re-install the new ones, the new ones are about 1/32" larger than original. The inner seal was included with the FK1203-1 kit and I have installed it but I do not have a like-for-like replacement for the outer seal.

According to all of the part number listing I have found online, the FK1203-1 is the seal kit I need but the spool outer seal doesn't seem to come in the kit. Were there multiple seal kits available at one time for the '92 Force 120hp?

Thanks for any guidance you can give.

That would be a Jerryjerry05 question; he usually responds during morning hours. I do have a ‘90 lower complete assembly; not sure if it’s a match but may be a part option if you’re not able to get what you need otherwise. Cheers!

 

[jerryjerry05]

Some of the bearing carriers only had 1 seal in the carrier.
The other seal could be for the drive shaft/water pump seal??

If yours had 2 then start going through the parts diagrams looking for the carrier with the 2 seals.