Replacing Water pump for the first time - 88/89 Mercury Model 80

[jmanng]

Hello all:

Replacing the water pump on our 88-89 Mercury 80 Outboard (3cly) for the first time and reading through the procedure in the manual. It instructs to first remove the gear housing (by following that section of manual) first (which makes sense). However, in that section, it also has you removing the Prop and prop shaft. I guess because of the jumping around that the manual does, I'm not sure if I need to do that part of procedure for a water pump replacement... In looking at the exploded diagram, it seems that the drive shaft will come out just by unbolting and lowering the gear housing/bottom end. Even with the drive shaft meshed with the prop shaft, it doesn't seem the drive shaft needs to be removed from the bottom end as the water pump is slid on from the top from (according to water pump procedure)... I guess I'm just not understanding why and want to get a better understanding if dismantling the prop & shaft is required (it looks like there's a fair bit of components to be messing with)... and having read some warnings about being careful not to bend the drive shaft, I would feel much better having a better understanding of this part of the procedure.

Also, in another thread, there was a link (dead) to a video on a TMD waterpump replace procedure that was supposed to be similar... anyone know where it can be found these days?

Thanks
Jaime

[gss036]

I've never done a 50hp, but you should not have to do anything with the lower end, they will just seperate when the bolts are removed(hopefully not a saltwater engine, had to use heat to get my 89, 200hp apart the first time) and give you access to the pump.

[phatmanmike]

very simple.

remove bolts from lower unit, i believe they are 5/8" should be a nut in the front, 2 on each side. also a 1/2" on top of the rear of the lower unit, that removes the lil trim tab steering tab . also should be a 9/16 on underneath side of wehere lower unit mounts to the motor, in the rear just in front of the steering tab thingy.

this is all from memory..........i may be close or way off, i think im close.

once all bolts are out, lower unit will /should fall out. watch your toes.

DO NOT grease the drive shaft where it meets the crank shaft. it will seal and seize together.

once its out and dropped, youll see the water pump housing clearly and the bolts needed to be taken out to get access to the impeller. DONT LOSE THE IMPELLER KEY. when you put the key back on , use some axle grease or sumthing to "hold" it in place while re-assembling the water pump housing.

[phatmanmike]

oh, dont need to remove drive shaft from lower unit.

oh, you wont bend the drive shaft, that thing is solid steel.

oh oh yeah, BUY A MANUAL!!!!!

[jmanng]

I've been re-reading the manual... I was reading to remove the prop in the gear section as removing "prop & prop shaft" (don't know why). It's much clearer reading it over a few times and your replies puts me at ease.

Thanks again for your replies!