Identifying a Jabsco Raw Water Pump

I have twin 1977 Detroit Diesel with Twin Disc transmissions in my Uniflite 42 Double Cabin.

I am attempting to rebuild the raw water pump due to leaking seals and bad bearings, but I can't identify exactly which model it is so I can order the parts.

It looks almost identical to this Jabsco 7420 series pump:

https://www.pumpvendor.com/media/jabsco/Jabsco_6400_7420_series.pdf

However, it does not have the plugs on the inlet/outlet ports and the dimensions are slightly different from the dimensioned drawing in several places, by 1/8" to 1/4" difference in places.

I hesitate to assume the internals are the same without a positive identification.

Any ideas on the best approach to identify it? Call Jabsco? Is there a reference manual that has all of their pumps that I could go through?

I found the 7420 by going through this list and looking visually to identify it.

https://www.pumpvendor.com/jabsco_flexible_impeller_pumps.html

Look on the cover plate. Some pumps have the model number stamped there, or on pump body.

I've looked. Unfortunately the cover plate only has the part number for the cover plate on it and that plate was used on a lot of pumps. It's not cast or stamped anywhere else on the body that I can find.

Try calling Depco Pump 800-446-1656, the link below will help identify pumps by specific Detroit engine.

http://online.anyflip.com/ucrc/jfuq/mobile/index.html#p=106

A good bearing supply can match the bearings and seals. I buy mine several at a time. I have twin DDs and a spare raw water and coolant pump for each. Any pump trouble (rare) and I just swap out the pump and rebuild it the next winter. Once rebuilt, I put them in a vacuum seal bag for long term storage. I got my spares on ebay, some new some needing rebuild. Same with other spares - injectors, starters, alternators, etc.

Tomas said:

Try calling Depco Pump 800-446-1656, the link below will help identify pumps by specific Detroit engine.

http://online.anyflip.com/ucrc/jfuq/mobile/index.html#p=106

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I looked through their catalog and nothing quite matches up. I'll give them a call next time I'm in front of the pump so I can answer any questions to identify it.

Lepke, which detroits do you have? My 671's have an externally mounted, belt driven pedestal pump which seems to be unusual based on the catalog's I've seen so far that show gear driven pumps.

sbman said:

Lepke, which detroits do you have? My 671's have an externally mounted, belt driven pedestal pump which seems to be unusual based on the catalog's I've seen so far that show gear driven pumps.

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Mine are gear driven on early 671s, but the same pump as most. Doesn't really matter, lot of trouble to replumb for gear drive pump. Depco can id the pump.

I called Depco on Friday and they were not able to identify the pump.

After doing more research, I have J&T Detroit 671N, so they were marinized by Johnson and Towers. The pump mounting and model number is specific to that installation.

I've got an email off to J&T to see if they have any old records. I tried calling them but there is something wrong with their phone system and they are not responding to calls. I'm also needing a couple of molded cooling hoses and part numbers would be really helpful there as well.

"I got my spares on ebay, some new some needing rebuild. Same with other spares - injectors, starters, alternators, etc."

Sailors know,

The best spares have been taken off the engine while in good condition, then saved.

They are sure they will fit and will work.

FF said:

"I got my spares on ebay, some new some needing rebuild. Same with other spares - injectors, starters, alternators, etc."

Sailors know,

The best spares have been taken off the engine while in good condition, then saved.

They are sure they will fit and will work.

Click to expand...

Tough to purchase any spare, new or used if you don't know the part identification.

I was able to talk to a parts specialist at J&T and they confirmed that the pump is a Jabsco 7420. The design has changed slightly over the years, but the internals should be the same.

"Tough to purchase any spare, new or used if you don't know the part identification."

True enough , but don't most parts catalogues have full sized drawings of pump impellers to make matching old stuff easy?

FF said:

"Tough to purchase any spare, new or used if you don't know the part identification."

True enough , but don't most parts catalogues have full sized drawings of pump impellers to make matching old stuff easy?

Click to expand...

I need more than an impeller, likely going to need a shaft and possibly a cam plate. There are no drawings I can find of these components, they are sold by model number. Glad to know what I have now, and happy that Johnson and Towers was able to help me with questions about a 40+ y/o conversion. Seems like a good company to deal with.