Leaking raw water pump

[noelex 77]

There should not be a lot, or even any grease. I would be concerned someone has used a lot to try and stop a persistent leak, or maybe even the impeller not priming due to a worn cam or pump housing.
Look for a worn (scored) shaft, or or cam.

Some of the rebuild kits include a new shaft and cam.

Don't worry about trying to save the rubber seals etc removing them usually destroys them and they are very cheap.
Some have a SS spring and some a mild steel spring, try to get the former if possible. When you find the right size order half a dozen.

[Astral Blue]

Thanks for the quick replies. The engine and pump only have a few hours on them. The engine is an old British military surplus unit that has never been put into service.

The shaft is brand new, no evidence of scoring whatsoever.

I'm guessing the only problem is the abundance of grease.

I'm going to order a new seal today. It is a $17 fix and easy to replace.

Thanks again for the help!

[zeehag]

found this late--i have 3 pumps for mine--one not rebuildable , one rebuildable, and one i purchased for cost from my yanmar man--he sent me packing with bells on my feets--this and some gifties--belts and small stuff--impeller---so i would have good fortune inmy adventures, and get out of his hair..lol----
my can be rebuilt pump was leaking for 1200 miles--we sealed it with grease and it worked for that long-when we pulled it and took it apart, the bearings were failing-- we took it out just in time--when the bearings fail, water goes into wrong places an blow engine.....
i now have my new pump installed--- buy some rebuild kits and a spare pump--you need one that is ready to install as a complete spare. yes mine is 4-108, also.

[Astral Blue]

Originally Posted by Albro359

The other issue is the shaft itself....
IF you have had a worn seal for long time you may find that the shaft is actually scored.
Replacing the seal on a scored shaft does little except wreck the new seal...
Check the pump shaft for scoring is my ...what do you yanks say ?...two penny worth..or ???

The engine has never been put into service. Hence, the pump and shaft are in brand new condition.

For those who need a shaft for this pump in the near future, S&W Diesel carries it for about $80.

[Jim Cate]

A couple of points:

A scored shaft can easily be repaired with a "Speedi-Sleeve" (or other brand name) kit. These are very thin sleeves that are slid over the shaft in way of the seal and restore the surface to like new. Commonly used in industrial maintenance, inexpensive and effective.

The lip seals are indeed very inexpensive if purchased from a typical bearing supply house. The ones for the Johnson water pump">raw water pump on our Nanni are around 22 bucks each from Nanni, and 2 dollars each from the bearing shop. Your choice! It is good practice to replace the little coil springs (whether s/s or not) with similarly sized o-rings, thus eliminating one common source of seal failure.

Wear on the cover plate is often an issue as well. On many pumps one can reverse the cover (outside to inside) and double its lifetime, or use the worn item as an excuse to buy a Speed-Seal cover which makes impeller access much easier.

Finally, the bearings can also be sourced from the corner bearing supply shop, and at vastly less cost than from Johnson/Jabsco or your friendly marine engine parts salesman. The bearings may require a press to install, although I've been able to use a bench vise and an appropriately sized socket wrench successfully on mine.

These pumps are pretty simple and well within the scope of DIY.

Cheers,

Jim

[Astral Blue]

Originally Posted by Jim Cate

A couple of points:

A scored shaft can easily be repaired with a "Speedi-Sleeve" (or other brand name) kit. These are very thin sleeves that are slid over the shaft in way of the seal and restore the surface to like new. Commonly used in industrial maintenance, inexpensive and effective.

The lip seals are indeed very inexpensive if purchased from a typical bearing supply house. The ones for the Johnson raw water pump on our Nanni are around 22 bucks each from Nanni, and 2 dollars each from the bearing shop. Your choice! It is good practice to replace the little coil springs (whether s/s or not) with similarly sized o-rings, thus eliminating one common source of seal failure.

Wear on the cover plate is often an issue as well. On many pumps one can reverse the cover (outside to inside) and double its lifetime, or use the worn item as an excuse to buy a Speed-Seal cover which makes impeller access much easier.

Finally, the bearings can also be sourced from the corner bearing supply shop, and at vastly less cost than from Johnson/Jabsco or your friendly marine engine parts salesman. The bearings may require a press to install, although I've been able to use a bench vise and an appropriately sized socket wrench successfully on mine.

These pumps are pretty simple and well within the scope of DIY.

Cheers,

Jim

Hi Jim... Thank you for your very helpful insight. Bearings and seals are always best to purchase from a bearing supplier. I have saved tons of money in the past using this practice. Even more, I have been able to obtain much higher quality seals than OEM specs. I ended up ordering this seal from a marine parts house (iboats.com) for a third of what Sherwood authorized dealers charge.

I will definitely keep the sleeve in mind if and when the shaft becomes scored. Thanks again!