Changing Sherwood Pump on 4.108

[jlogan]

I want to swap out the Sherwood pump on my 1980 or so Perkins 4108 for a completely new one. Is it as simple as removing the four nuts that hold on the old pump to the front of the engine block and replacing the pump with a new one, or is there some sort of alignment and seal replacement in the block side that will have to take place once I pull off the old pump?

thanks

[btrayfors]

Email me: bill at wdsg dot com

....and I'll send you a pdf with pics and parts list for both the water pump">raw water pump and the circulating pump.

Bill

[Chief Engineer]

no alignment....put a new flange gasket on...buy a rebuild kit for the old pump.

And as you sit an a tranquil anchorage, with the warm tropical breezes wafting the smells of the islands to your boat, in the late afternoon....rebuild the pump.

Originally Posted by jlogan

I want to swap out the Sherwood pump on my 1980 or so Perkins 4108 for a completely new one. Is it as simple as removing the four nuts that hold on the old pump to the front of the engine block and replacing the pump with a new one, or is there some sort of alignment and seal replacement in the block side that will have to take place once I pull off the old pump?

thanks

[bfharris]

I did a search on this type of topic and this was the closest I found, so I hope I am posting in the right spot. I have a Catalina 27 with a Universal M18 that has a Sherwood pump on it. Today I discovered the pump leaking around the bottom nut that holds the pump to the block. Could be a faulty gasket, so I plan to remove it and check it out, but wanted to make sure it is as simple as that. I've worked on many cars over the years, but have no experience with a marine diesel. There are 4 nuts holding my pump to the block. Is it safe to unbolt, inspect, replace gasket, and just bolt back together?

Thanks!

[bfharris]

I think I may have found my answer with the exploded view of the pump on MarineDieselDirect.com.

[donradcliffe]

Going from memory, I think the pump mounts with 4 bolts to a flange which mounts with 4 bolts to the engine. If you just take the pump off, everything is OK, but if you loosen the wrong 4 bolts you will need to realign things or the pump drive will rapidly chew itself up.

Rebuilding 4108 pumps in tropical islands brings back old memories--I think we had a 3-boat rebuilding party somewhere in French Polynesia about 10 years ago, and ended up with 7 workable pumps.

[bfharris]

I should have reported back, but I ended up rebuilding my pump last Friday. There were 4 nuts holding it on to the block. One nut was so badly corroded, I had to take the stud out instead. Replaced inner/outer seals, impeller, gaskets, one stud and four nuts/washers and bolted it back on. My main concern was how the shaft from the pump connected to the shaft in the engine, but once I had it off I was relaxed to see it was a simple tongue/groove. So I am happy to have that all done. I have years of experience with gasoline engines, but am learning diesels.

My vessel is a 1988 Catalina 27 with a Universal M-18.