1972 mercury 800 water pump question

[Gomer50]

I am a little concerned about a new water pump.I ordered a new complete water pump from iboats and installed it.But before i put the lower unit back on I would like to know is it hard to turn the drive shaft after the new pump is installed.Mine sure is.I didnt wrench it down real hard,it just tight.Any Ideas

 

[Gomer50]

Re: 1972 mercury 800 water pump question

Just to add the lower unit is in neutral and turning it clockwise is pretty hard.

 

[Faztbullet]

Re: 1972 mercury 800 water pump question

Did you grease the cup the impeller spins in the upper housing ? If not yes it will be tight and stiff...

 

[Gomer50]

Re: 1972 mercury 800 water pump question

oh its all greased up made darn sure of that,didnt want to burn up the impeller just in case.

 

[Gomer50]

Re: 1972 mercury 800 water pump question

I just want to add when I purchased this lower unit I changed the impeller but didnt look at anything else.As I stated I went ahead and ordered a complete water pump set,so when I took the complete water pump off I noticed there were 2 shim washers laying on top of the bearing and the water pump base,Now to the best of my knowledge they should be if needed under the bearing.No water in the lower unit however.

 

[Chris1956]

Re: 1972 mercury 800 water pump question

I never saw shims on top of the driveshaft bearing, however, Merc did make several different styles of LU. Check the parts list on Crowleymarine.com for that exact motor, and see if shims are listed.

Make sure the driveshaft is cleaned and lubed before installing waterpump base, or it will tear the seal.

 

[Moody Blue]

Re: 1972 mercury 800 water pump question

Yep, a new impeller will tighten things up for sure.

Those shims must be reinstalled as found under the lower pump housing. They determine the backlash of the gearing in the lower unit. Take out those shims and you're asking for big trouble.