Re: Water pump replacement on 1980/1981 Mercury 9.8
you dont need to buy the owners manual. go the sticky at top of the post and look on-line. I just replaced mine in my '84 9.8.
you can do it if you understand righty-tighty - lefty-loosy
put motor in forward
remove nut under andi-cav plate above prop
remove nut at front of foot
use rubber mallet to tap foot if it has not already come loose
pull foot from center section
the water pump feed tube will most likely come out with the lower
pull two nuts from top of water pump
remove top of water pump
inspect the bottom of the pump cover - if there is any signs of melting of the plastic, buy a complete whole new pump, and not just the impeller
take a picture to note the direction of the impeller vanes (or make a sketch)
pull impeller out with a pliers
pick up the key that fell out when you did that
inspect the lower - if there is any signs that the lower has overheated and the plastic is a bit melted, buy a complete pump assembly and not just the impeller
if the pump housing needs to come out, then remove the drain plug and remove the gear lube (tell you why in a moment). then you need to gently pry up on the water feed tube
pull the pump body up - there is an o-ring at the bottom of the pump body that seals the case
if you didnt drain the case, there is now gear oil running down your shirt and into your shoe
take new pump assembly and put o-ring on the bottom section of pump.
put a small amount of grease on the o-ring
install water pickup tube and pump together, using a sealant to seal the pickup tube to both the casting and water pump. I used 3M 4200
now if your just replacing the impeller -
clean out the small amount of debris in the lower portion of the pump housing from the old impeller
put a dab of grease on the key to hold it to the shaft
put a bit of dish soap on the impeller vanes
put impeller vanes in same orientation as your picture or sketch
Follow instructions on the remainder of the parts in the kit such as the wear plate, misc seals, etc.
install the pump cover
torque the two nuts
install the water tube into the motor - sealing the top of the tube to the power head (never try to install the water tube to the pump first, it will never hit the hole
install lower to the mid section of the motor
you will have to line up the water tube with the pump outlet
you may have to turn the prop a bit to get the drive shaft to go in.
replace the two nuts you removed in the beginning
replace the gear lube
now would be a good time to replace the thermostat as well. the kit should have both the t-stat, o-ring and the body gasket
test the motor in a pail
make sure that there is water from the teltale.
go boating
