1977 85hp water pump question

[fdmsiv]

Just dropped the lower unit on this engine and began to dissassemble the water pump. I removed the cover (plastic), impeller, and plate. The first thing I noticed was a rubber gasket under the plate. This is kind of strange because all of the exploded views of this section that I have seen do not show a gasket (view taken from brp catalog). I am thinking the previous owner didn't pay too much attention to what they installed.

Do I need to replace the gasket, or go with what the catalog shows (plate only?)

The plastic pump housing is toast and I need to replace. During my part search I came across a chrome pump housing. Is this worth the extra $25.00 or should I stick with the plastic? Motor will be run in brackish water, willing to pay if part will last.

Finally, this should probably be a seperate post but here goes. I can only move the shift rod up and down maybe a half inch. Is this something to be concerned about?

Thanks in advance

 

[Randybeall]

Re: 1977 85hp water pump question

Many engines use an o-ring below the plate, some use a gasket. There should be some sort of seal in this area. I would look for an o-ring groove and install the correct o-ring if there is one, if not a gasket would go in. The chrome lined housing is for running in water with sand or silt present. I would use it as insurance, will definately last longer and may be smoother for the impeller to run in.
Shift rod should only be moved with the shaft turning, spin it with your hand and try the shift. Have fun.

 

[Joe Reeves]

Re: 1977 85hp water pump question

When you say "under the plate", that can be somewhat confusing.

The plate is normally looked at as being the large flat plate between the water pump housing and the lower unit. I know of no rubber gasket in that area.

However, if you're speaking of the area between the impeller cup and the plastic water pump housing, the housing has a recess there where a flat rubber washer or a O Ring would seat which would be compressed when the cup is installed.

 

[ezeke]

Re: 1977 85hp water pump question

You need to move the driveshaft while raising and lowering the shift rod. If the propeller turns in both directions in response, you should be OK.

 

[fdmsiv]

Re: 1977 85hp water pump question

Thanks everyone for the responses!

Joe Reeves, thank you for your input, I was talking about between the flat plate supplied with the rebuild kit and the lower unit.

Does the shaft need to be spinning at a certain rpm before shifting into gear?

 

[ezeke]

Re: 1977 85hp water pump question

There does not need to be much speed because whenever the driveshaft turns all of the gears are moving. The system uses hydraulics, so it works more easily with the gearcase filled.