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Lost another raw water pump

CaboJohn

Regular Contributor
I have twin 2003 Captains Choice 5.7. Raw water pumps are crank mounted Sherwood P-105. They used to last quite a number of years but lately I seem lucky to see two years of service...less than 200 hours. Failure mode is always a salt water drip at the shaft seal. I saw today the starboard again has a drip. Port was replaced several months ago.

It is kind of a reach around blind mount but I take care to mount it solid and check for wobble after mounting. Same life issue on both motors. I thinking maybe the pumps are not as good as before? Or maybe I'm not!

I have to loosen the anti-rotation arm to get the pump mounted. When I tighten it back on block perhaps it puts a load on that is not needed. I have read on this forum that some members just use the hoses to stop rotation. Might that help? Hoses are original so I might be a little nervous about putting a new load on them.

Or perhaps another brand of pump (Johnson?) has a better seal. Are there different types of seals available in pumps that will fit on this engine? (I have plenty of room in front of the pump).

Back when I could always find one on sale for less than $200 it was not so bad. Now the best prices seem to be about $300.

I will order a new 105 next week, in the absence of some good advice or suggestions. Anyone have a good idea?
 
Why are you replacing the whole pump and not just giving it a rebuild John. Its a bit of work but bound to be cheaper
 
As for the rebuild, I once read it is difficult and you need a press. At the time the kit was over $100 and a new pump was less than $200 so I did not bite. Has anyone done a rebuild with new shaft seals? How easy was it?

As for the F5B years ago I ordered one but it was clearly smaller in capacity than the P-105 so I returned it. I did not try the F6B, a bigger pump, as it was more expensive at the time than the P-105. I think now it is less.
 
You do need a press , other then that it was not that difficult. I took the pump over to a buddy's and if memory serve I think it took us about ten minutes to press out the old seals and less then that to put the new ones in.
 
2X on the press....

Can't say that I've done P105 but plenty of cooling pumps. Most are straight forward and fairly simple. Sometimes a snap ring is tricky to access and a few need a bit of searching to find the right sized mandrel for but nothing difficult. putting the seals in, in the proper order, is also easy as long as you pay attention during disassembly or have access to the correct service data...
 
i might try it. Going to the Harbor Freight site (my source for cheap tools I might only use twice a year) I see a manual 1 ton press is $60 and a 6 ton press (that uses a rube goldberg framework holding a 6 ton bottle jack) is $70. Is 1 ton enough? I like the looks and size of the smaller unit if it will do the job.
 
We used my friends big floor press because that is what he has but I can't imagine you would need much more then the 1 tone.
 
1 ton should be adequate.....the big think to make sure is that the frame won't distort when you put the load on it.....not being square will cause all kinds of issues...
 
As for the rebuild, I once read it is difficult and you need a press. At the time the kit was over $100 and a new pump was less than $200 so I did not bite. Has anyone done a rebuild with new shaft seals? How easy was it?

As for the F5B years ago I ordered one but it was clearly smaller in capacity than the P-105 so I returned it. I did not try the F6B, a bigger pump, as it was more expensive at the time than the P-105. I think now it is less.

The F5B-9 is the small volume seawater pump...... the F6B-9 is the large volume.
Either mounts identically!



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