Fresh Water Impeller Replacement Cycle and Challenge finding the part

[Ran-Dee9229]

I have an M-12 two-cylinder 10 HP Universal Diesel inboard motor in my 1984 ODay 28. I replaced the fresh water pump 4 years ago. I replace the sea water impeller every year.

I went to order a replacement impeller (301339) for the fresh water pump (UNV-301336). I'm told that is an obsolete part that I can only get as part of a complete replacement of the fresh water pump. My questions are:
1. How often do most boat owners change the fresh water impeller?
2. Does anyone know where to get this part?

I'm a sailor so the motor gets only modest use starting and end a day of sailing. Last year I moved from Maryland to New Bern NC which entail quite a bit of motoring in the ICW.

 

[capta]

If you have the proper zincs in the system and use a good quality rust inhibitor, the fresh water pump on a diesel should outlast your ownership of the boat. I don't know that engine, but every fresh water circulation pump I've seen on a diesel has been a centrifugal pump (just like on your car) without a replaceable impeller.

 

[Ran-Dee9229]

thank you so much, I just learned that to be true from my calls with parts dealers.

 

[BarryL]

Hey,

While you can't buy a replacement impeller you probably can buy a rebuild kit. This will come with new bushings, bearings, etc. Note you will need some skill to successfully rebuild the pump.

Also note that many Universal Diesel marine engines are based on Kubota tractor engines. There are parts cross lists available. I was able to buy a Kubota pump for less than half the cost of a Universal Diesel pump. The actual pump appeared the same in every way (minus the green paint).

Barry

 

[Benny17441]

I think we have a problem with parts nomenclature. We have the sea or raw water pump impeller and we have the engine coolant pump. The engine coolant pumps are one of those items that " if it is not broken, do not fix it". Yes periodically check it for leaks at the weep hole, listen for bearings wear and check for any pulley play. Also make sure the coolant is kept fresh and add a rust inhibitor and pump lubricant. The raw water impeller should be inspected once a year and immediately after the engine experiences an overheat. I carry a spare raw water impeller and will replace the coolant pump if the bearings start getting noisy or if I detect a leak starting.

 

[Stu Jackson]

Yes periodically check it for leaks at the weep hole

IIRC, there are no weep holes on the coolant pumps on Kubota engines. There are weep holes on the raw water pumps (Oberdorfer, Sherwood), which are add-ons to marinized Kubota engines by Universal, which are in the physical place of the hour meters on tractors.

 

[jviss]

physical place of the hour meters on tractors.

I'm pretty sure it's in place of the hydraulic pump, no?

 

[odaydokay]

I guess I am confused also. Anyway, I got 25-28 years out of my Sherwood pump before it started to create problems. Depco rebuilt it once but that was it and so I went to the better Oberdorfer, whose impeller is not interchangeable with the Sherwood. I guess in the 25-27 I only replaced the impeller 2-3 times, but I am not a heavy user of the motor either. I have a spare new in bag impeller (33100) for the Sherwood if you want it, PM me. Ship charges only.

 

[Stu Jackson]

I'm pretty sure it's in place of the hydraulic pump, no?

We have the tractor parts manual on our C34 website and a few months ago I went into our local Kubota tractor dealer and got a gasket --- for my Oberdorfer raw pump --- by ordering the hour meter gasket from the tractor manual.

The hydraulic pump in that tractor manual is poorly shown and hard to tell if that's where it is, but the gasket looks entirely different.

You could look: http://c34.org/wiki/images/a/a2/B6200D.pdf