Perkins 4108 raw water pump

[Jeff Peterson]

The yard commissioned the 4108 on our CD 36 today and reports a small leak from the raw water pump. They are suggesting that it be replaced. We had a new pump installed in 2011 and periodically replaced the impeller. Does anyone have experience solving leaks from these units that might avoid a replacement? There is both a Jabsco or a Sherwood option for replacement part; does anyone have a reason to go with one or the other? Thanks

[John Danicic]

Jeff:

In the twenty years that I have owned Mariah, I have had the Jabsco raw water pump rebuilt twice now. It seems that they work good for a few years and then start to drip a bit, then a little more. I live with it for a while but watch it. I Just had it rebuilt two years ago and will find out how it's doing in a few weeks. Rebuilding is pretty straightforward and not anywhere as expensive as a new pump.

As in all things when it comes to a Perkins 4-108, "attention must be paid". Keep an Eye on her and attend to all the various leaks.

[John Danicic]

Jeff:

In the twenty years that I have owned Mariah, I have had the Jabsco raw water pump rebuilt twice now. It seems that they work good for a few years and then start to drip a bit, then a little more. I live with it for a while but watch it. I Just had it rebuilt two years ago and will find out how it's doing in a few weeks. Rebuilding is pretty straightforward and not anywhere as expensive as a new pump.

As in all things when it comes to a Perkins 4-108, "attention must be paid". Keep an Eye on her and attend to all the various leaks.

[Jeff Barnes]

In my experience, there is a trade off between rebuild and replace with these pumps. A replacement, notwithstanding the ridiculous price (either Jabsco or Sherwood) seems to last longer than the rebuild. I rebuilt a Sherwood and it didn't last that long. Finally replaced it and no issues years later. The main difference in the two pumps is the number of screws holding the cover plate and the inlet/outlet configuration. If you switch brands plan to do a little re-plumbing.

[Mbigos]

I have the same issue. the boatyard saw spot rust on the engine mount crossbar under the water pump. I am going to watch it as I always have. Its dripped for 5 years, about one drop every 45-60 seconds.
I plan to wire brush the crossbar, and as Dave Perry told me once, give it "a spraypaint tune-up" with the old tractor-blue engine paint.
I'll put another $400 in the bucket for when I decide to get a new engine, new water pump, or rebuild the water pump.
I say all this in the context of having attended to several other issues with discipline. This spring, I installed a new solenoid on the starter. 5 years ago I replaced the internal freshwater pump because it was losing antifreeze. These engines are quite serviceable. I kinda like the farm-technology aspect of them, but there isn't much space in there. Fair winds and following seas,

[John Nebilak]

I have rebuilt the raw water pump numerous times using the rebuild kit. The only part that I have found that wears out most frequently is the shaft seal. Mostly due to corrosion on the shaft from salt water. The important thing to do when rebuilding is to make sure the shaft has as good a finish as possible using very fine emery cloth. A "mirror finish" would not be overstating the level of smoothness although it is difficult to achieve. Cheers

[John Nebilak]

I have rebuilt the raw water pump numerous times using the rebuild kit. The only part that I have found that wears out most frequently is the shaft seal. Mostly due to corrosion on the shaft from salt water. The important thing to do when rebuilding is to make sure the shaft has as good a finish as possible using very fine emery cloth. A "mirror finish" would not be overstating the level of smoothness although it is difficult to achieve. Cheers

[Kailua Kid]

Once the shaft seal starts to leak, the water will begin to get into the pump bearings, with obvious consequences. I would rebuild now, or at least replace the shaft seal. Of course, once you have it on the bench, why not rebuild the whole unit, right? As noted above, the shaft wear surface must be mirror smooth and clean or the seal will quickly fail again. There are numerous YouTube videos showing proper (and not so proper) ways to replace the seals and bearings and wear plates in those pumps without a press.