Anybody try rebuilding a Sherwood seawater pump?

I'm the kind of guy who likes to replace stuff before it fails. My Cummins engines have the common Sherwood P1730 (don't know if they're -A or -C suffix) seawater pump. I just bought the boat this year and have no idea if the current pumps are original or have ever been rebuilt. The engines have about 900 hours on them.

My idea is to buy two new P1730C pumps early next year to keep as spares, and next year when winterizing instead of replacing just the impellers I'll replace the pumps. Then I would like to buy major rebuild kits and rebuild both pumps at my leisure. Has anybody attempted a DIY rebuild of this pump? It looks like the hardest part is using a puller to remove the gear from the shaft. However, since the price of the major rebuild kit is about 75% of the cost of a new pump, maybe I should just keep the old pumps as spares to use in an emergency without rebuilding them, since the new pumps should last several years at least.

check out sbmar.com and the SMX water pumps. far better built, and a much heavier duty impellar.

I have 17XX Series Sherwood pumps and about 1500 hours on my engines. I've owned the boat since 1997 and am in salt water with a shallow sandy bottom, so I've had some experience with pump wear/failure.

The early Sherwood 17XX series pumps pumps usually hit point at about 500 hours when they start leaking from the seal on the end away from the gear. I have found that you can rebuild them; the rebuild is pretty easy, but not cheap. When rebuilt, you have an old pump with some new parts in it, so your next leak/rebuild comes sooner than the first, at a few hundred hours. Given the rebuild cost, I chose to replace the pumps the 3rd time around. I am at about 700 hours on a set of the new series 1700XX pumps and so far they are lasting longer than the early series.

If were you, I wouldn't buy new pumps then store them a year. The impeller dries out and takes a set from being compressed in the pump housing. I would replace the pumps now so you know you have good solid pumps cooling your engines. If your present pumps are not leaking, put an impeller kit in them ($70 ea.) and keep them for spares if you wish. However, take a look at the pump location and ask yourself if you will change the pumps while away from home, at sea, or in a transient location. If you won't, then why take along a spare? You can run a lot of hours and miles on a leaking pump.....and that is where a pump will most likely require changing. If you just lose some impeller blades, an impeller kit, not a whole pump is a far simpler solution. Sometimes you are lucky and you can pry the drive gear off the tapered shaft, but it usually requires a press. Unless you are willing to equip your spare pumps with drive gears so all you need to do to change pumps is remove the old one and stick the replacement, drive gear and all, on the accessory drive housing, then I wouldn't bother with carrying a spare pump around with me. Finally, the pivotal issue with rebuilding a seawater pump is the seal integrity. If the back side of t he pump leaks, all you get is some water in the bilge, but if the front seal leaks, you can dump a bunch of seawater into the timing cover and oil pan.

Thanks, Frank. If I understand correctly, the P1730 pumps had a design flaw that resulted in broken shafts, which is why Tony Athens designed the SMX pumps that CougarCruiser is suggesting. However, around 2002-2003 Sherwood came out with the P1730C version that alleviates the design flaws, and rebuilding an older pump with the major repair kit essentially upgrades it to the 1730C design. I'm sure the SMX pumps are nice, but I can buy two new Sherwood pumps for $860 including shipping. Two SMX pumps from sbmar would be $1,500.

fwebster said:

Unless you are willing to equip your spare pumps with drive gears so all you need to do to change pumps is remove the old one and stick the replacement, drive gear and all, on the accessory drive housing, then I wouldn't bother with carrying a spare pump around with me.

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Don't new pumps come with the drive gear? The ones I see online seem to have the gear installed, like this one: http://marinepumpdirect.com/sherwood-pump-p1730c/ On a boat like mine I've heard it's easier to replace the entire pump on the port-side engine than it is to replace just the impeller.

I cannot answer your question. I have the 17XX series pumps on Caterpillar engines and the Cat pumps do not come with a drive gear......I suspect all you would need to do is to verify the Cummins application with DEPCO or whomever your pump vendor is. As far as accessability goes, the engine with the pump on the outboard side can be a bear to just get to. The marina a small mechanic and they pay for his gym membership, so this is one of those things where it is a lot less painful to write a check and let the spider monkey mechanic change the pump/impeller on the outboard side.