TOPIC: Lower unit options - 1968 1000SS

Hi everyone.

I dropped the lower unit off my 1968 1000SS recently and its not in the greatest shape. Its a standard 20" shaft.

A new water pump and upper housing is needed, however, the drive shaft is quite pitted around the top pump seal. I haven't yet got the lower housing out, but would not be surprised if the shaft is also pitted at that seal.

So I got to wondering, when did Merc move to stainless shafts and up to what year/model could I do a direct swap of the lower unit?

Thanks,
Aaron.

Unlike OMC motors, the Mercury brand stuck with carbon steel shafts till the mid 70's.

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Using speedy sleeves is one option for repairs.

A further question on this…

I have the new water pump kit on order.

Given the pitting on the shaft at the top seal, am I going to just destroy the new seal if I don't do something about the shaft condition first?

Was also wondering where there is a good online supplier of tinned marine cable? I need to replace a few of the cable on the motor's loom.

Thanks,
Aaron.

dont worry about the seal on top of the pump cover.the seal in the pump base is the one that holds the oil in. make sure you use the slinger above the pump cover and you will be fine.

Ok, another question…

New water pump installed. Prior to dropping the lower unit I put it in forward. I took photos when I dropped the unit and made sure everything was in exactly the same place (though now cleaned and with fresh grease (i.e. I’d have thought everything would move more smoothly)

When I reinstalled the lower unit, everything was still in forward (lower unit and forward control).

Once installed, shifting from the forward control was really stiff and I can no longer select reverse.

So I dropped the lower unit again, put both forward control and lower unit into neutral and reinstalled. Same issue. No change.

What have I done wrong or missed???

I can get it from forward to neutral and back, but the leaver is really stiff and I have to go past neutral to get it out of forward and into neutral.

Thanks,
Aaron.

check your reverse locks and tilt pin. the motor MUST be down on the tilt pin and reverse locks closed around the pin to work or you can damage your controll