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1979 80hp water pump question

S

Sails

New member
I have a 1979 80hp Merc that I am trying to resurrect. replaced the starter solenoid, put new gas and plugs in and it fired right up when I stuck it in the lake to see if it would run.:D

My question is, how do I tell if the water pump is working?
It would be a shame to burn it up since it seems to be running so well.

Thanks for the help!
 
This model like many others has a pump flow indicator known as a pee hole. When the motor is running it should be shooting a stream of water above the lake water level out the bottom of the lower cowling. That being said, if you are resurrecting an old motor, just replace the impeller. The fins on them are constantly bent back, and eventually lose their spring and don't pump water like they should. Mercury engines in this year are very easy to replace the impeller on. Just unbolt the lower unit and it drops right off. The impeller housing is on top of the lower unit on the drive shaft. If you need help from here let us know, but don't run it without replacing that impeller.
 
Interesting, I guess I will order a water pump kit since I am sure that I will have to replace gaskets as well as the impeller.
I did not realize that it was that easy to replace.
Thanks!
 
thebubba said:
If you need help from here let us know, but don't run it without replacing that impeller.
Click to expand...
Well I guess I need a little advice!
I have removed 7 bolts that are used to hold the lower unit in place and have partly gotten the unit off.
It has come about 6" out and seems stuck.
There is a rubber tube that is held by a plastic cable tie that seems to be stopping the bottom from coming out.
I think it may be part of the speedometer setup and figure that a heat gun may loosen it enough to come off.
My question is what else could be holding the lower unit from coming out?
Motor is in neutral, on the till support and all th bolts are out.
Have I missed anything other than the hose that could be holding it?
Thanks!
 
fastjeff said:
Nothing else. Yank away.

Jeff
Click to expand...

Thanks! Once I heated up the plastic tube and popped it off the lower unit literally dropped out!

One note if someone else heats up that tube, be gentle since it distorts really easily. It reforms just as easily if a little care is taken with the heat gun and a bolt of the right size.
 
Okay, I yanked and have replaced the impeller and seals etc.
Now my problem is getting it all back up and in!

Is there any secret to aligning the drive shaft gear so that it will go back up and in or is it just trial and trial turning the shaft a bit at a time?

Thanks for the help!
Ken
 
Put the shift above and the cam below in forward. Using a bungee cord to support the weight, start putting the LU back up. Be sure the water tube goes into the pump, then rotate the flywheel by hand to get the splines to line up. Finally, wiggle the shifter a bit--just a bit!--if it's being stubborn about engaging.

Jeff
 
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