1975 Merc 4.5 HP Lower Unit

[2loons]

First time poster here from Maine and hope someone can help! I just rebuilt my waterpump in my '75 Merc 4.5 HP successfully. Problem is I cannot get the lower unit/driveshaft properly lined back up while mating lower unit to the leg of the motor. when I try to line up, seems to hang up and stop during reinstall. I think it has something to do with the shift lever position maybe? My Seloc manual says to put shift lever in forward, and while turning flywheel line up lower unit/driveshaft splines and reseat. Any suggestions to get this thing to mate back up again? Thanks all!

 

[2loons]

Re: 1975 Merc 4.5 HP Lower Unit

Maybe I should be more specific. The Seloc manual for this lower unit (1975 4.5 HP Merc) is a type "B" model.

 

[2loons]

Re: 1975 Merc 4.5 HP Lower Unit

Success! although I didn't get a response on my issue, I did review lots of old messages and remedies to get my Merc running again. Fired the 4.5 up in the barrel today and shot a strong solid stream of water out the pee tube. ran about a good half-hour through the gears and stopping and starting several times and WOT. Before that, I cleaned the carb and fuel lines, runs even better. So in retrospect, using a Seloc manual and finding some good tips here on this forum paid off cause i'll be on the lake tomorrow! I'd be happy to share some of my repair experience I had with my lower unit if anybody needs a hand.

 

[paulgp6022]

Re: 1975 Merc 4.5 HP Lower Unit

What was the final thing that got it in for you?

 

[2loons]

Re: 1975 Merc 4.5 HP Lower Unit

It was really having an extra set of eyes next to me while I slid the unit back up into the housing. The rubber tube coming off the top of the water pump was catching on that small round metal sheeve that the drive shaft passes through in the leg. We just ensured that with the rubber water tube still properly connected to the metal tube in the leg, we lifted the lower unit up off center ever so slightly to pass over that sheeve and it slid right up into place like a glove. George over at John's old Merc site suggested putting it in upside down to see better and it worked!