Raw water pump wear question

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.

mike66

Guru
Joined
Oct 7, 2014
Messages
525
Location
USA
Vessel Name
Susan Helena
Vessel Make
Albin40
Hi all! How much wear is acceptable on the cover of my Jabsco raw water pump? Mine has a groove about the depth of a piece of paper. The outside of the cover has stamped information, but is otherwise smooth. So options: go with it as is, flip the cover around, or get a new cover ( and inside wear plate). No issues presently, just routine 2 year impeller replacement time.
Thanks.
 
on my sherwood raw pump, that plate is reversable and as it is made of bronze, will wear some from contact with the impellor.

I will flip it every couple of years (250 hrs or so) when I can see/feel the groove
 
THere is a limit to the acceptable wear before the contact between the impellor and the end plates becomes to much. Once there is too much wear the water pumping will drop and the ability to self prime will be lost.

Same goes for the back "wear" plate. Some pumps have the wear plate, some do not. If no separate wear plate then the pump body may need to be replaced if the wear gets bad enough.

My 40+ year old pump has had both replaced, the front several times now, the back about 10 yrs ago. Before I forget the 1/2 cam was also replaced 10 yrs ago.

Once the plate shows a distinct groove start thinking about replacement.
 
I think you're good to go until your next inspection. The jabsco cover shouldn't be reversed because it has part numbers stamped into the outside that would chew up the rotor.

Wiggle and check the shaft/bearing for play or roughness, assuming you have pulled the pump out. Got 5 years/several hundred hours on mine before a complete rebuild.

Edit: Jabsco doesn't seem to sell the ball bearings as a jabsco part, had to go to my local bearing guy for that, common parts.
 
Last edited:
Thanks all. I found a source for the cover, wear plate and cam, so I've ordered them and will replace sometime down the line. I didn't remove the pump yet, though I have to in order to remove the cam screw. Good point about the bearings.
 
Go to a glass store and get a hunk of 1/2 inch or thicker plate glass about a square foot from something broken there recreating and have the edges ground smooth .

Put a sheet of fine emery cloth on the glass and rub your old cover till its flat.

Store it on the bottom of a drawer , there really handy.
 
Thanks. Yes I used a flat piece of steel instead of glass. Didn't completely remove the groove, but cleaned it up nicely. Bit the bullet and have a new cover, wear plate and cam on the way.
Replaced impeller only at this point. The old one looked pretty good, no missing blades or cracks in the vanes. I also replaced the female spade connector on the engine sending unit which had some corrosion. Now I'm reading 10 degrees cooler on the gauge. Wish I did one at a time so I'd know which or both operations caused this. My header tank read 180 with the IR gun always, but the gauge fluctuated between 190 and 200. Now it sits closer to 180.
 
On my boat, the RW strainer is above water line. When the pump gets to the point where the strainer becomes empty over a day or two, its time to deal with the pump. Scoring of the main body or the cover allows air to transit the pump.

The plate glass is a good trick. I've done it to oil pumps too.
 
More free advice if you have to do bearing r & r: put the shaft in a baggie in the freezer, bearing outside in the sun on a hot surface, eases assembly, a dab of never seize helps too. Press only on bearing ID race.

Then freeze the shaft/bearing assembly and heat up housing in the hot sun, press the static seal into the housing flush with the housing surface, which is slightly below the inner wear plate. Be sure it goes in flush and straight with a tool that matches the OD of the seal can, no second chance to adjust it.

Then run the frozen shaft assembly into the warmed up housing and press to bottom of the bore on the OD of the bearing only. Easy peasy.
 
Update...replaced cam, wearplate and cover. Running at a steady 170 now at all rpm. I was at 180-190 depending on speed.
Guess it makes a difference.
 
Back
Top Bottom