Broke down - Freshwater Coolant Pump Model and Source

[rmbrown]

Mine's the M35A.  Here's my old pump.

[KWKloeber]

Mike:

re different sized gear covers... can you elaborate?  I bought and installed a new pump a couple of weeks ago.  It fit back together no problem, but I'm wondering if the pump wheel inside might be smaller diameter than intended reducing flow.  It is equivalent to the one I'm replacing but that one might not have been correct either!

Mike

That original caution was to Breakin, who has a B series.
The B/non-B series parts have nothing at all to do with each other.  I should have noticed your profile and avoided the fire drill.

There were different gear covers on the non-B engines, but it has to do with two different diameter crankshafts, not a larger water pump.

-k

[Breakin Away]

Obviously I measured the wrong part of my pump. I did not realize that half of the impeller housing was built into the outside front engine casting.

FWIW, the two top screws are spaced 2-5/8" apart. Does that narrow it down a bit?

[KWKloeber]

The pump housing ( pump land if you want to call it that) is built into the gear cover.

What are we trying to accomplish? Do you think you have the wrong pump? It's a gray market or Kb? Is there a coolant flow problem?
As I said to Mike, the messicks website shows both part numbers in stock, possibly the parts folks or your local dealer would measure both pumps for you (impeller and bolt separation)?  I don't know the difference between the two gear cover P/Ns, but presumably different impeller/pumps might mate to different size "pump lands" on the covers????

K

[Breakin Away]

I have not yet purchased a pump. I am still fiddling with hose connections, and placing dry paper at various places to trace the exact origin of my leak before I conclude that it's the pump. I think it's likely the pump, but not ready to pull the trigger yet. My measurements and related questions were intended to ensure I get the correct one when I am ready. Still debating between genuine Wb, genuine Kb, or Indian knockoff.

Thanks for your help.

[Breakin Away]

Quick update on my status:

Due to two weeks of business travel I haven't done anything except monitor seepage upon my return. There are definitely a few drops per day of coolant coming out somewhere. One small piece of paper towel that I left was saturated (but not dripping) when I returned. The others were completely dry, so I have a general idea where the leak is coming from, but still can't see the exact source. I've decided that I need to remove the water pump pulley to try to get a better look. The pulley's shape appears to be a cup that covers much of the pump bearings, and I have a feeling that the leakage may be going into the cup first before oozing out onto the gear cover. This may also create corrosion problems inside the cup that I should inspect.

I have a few extremely basic questions which I can't find answered on the wiki:

• First, I need clarity on how best to de-tension and remove the belt. It looks like the primary source of tension is the alternator, and if I loosen its attachment to the bracket I will get enough slack to remove the belt from the pulleys. (Obviously the belt itself is held captive by the raw water hoses.) It this correct?


• Planning ahead, when I go to reassemble everything, are there tricks to tensioning the belt again? Is there somewhere I should stick a tool to get leverage in re-attaching the alternator to the bracket with sufficient leverage to establish tensions? (Sorry if this is too rudimentary, but I don't like to assume anything.)


• I've noticed a small amount of corrosion in some of the pulley grooves, perhaps from last year's raw water bearing leakage getting some moisture on them. Should I take this opportunity to get a rotary brush to knock off the rust and perhaps re-paint the pulleys? Or is this just not worth worrying about? If I paint them, is there a suggestion for what matches the Universal light green metallic? Or do I have to go to Westerbeke for that?


• Finally, if I'm going to open up the coolant system for the pump replacement, I should replace the coolant which is at least 3 years old (maybe more). Is there a recommendation for how to go about replacing this? Do I try to drain the whole system, or just push through the old coolant with new stuff? Please note that my hot water heater is in the MkII location down next to the batteries in front of the galley sink and refrigerator. That means I have a low point in the loop that is extremely hard to reach. Adjusting those fittings is almost impossible.

[Breakin Away]

Hi all, I hope you had a great holiday weekend! Here's a brief update on my prior post.

I was able to remove the water pump pulley without first de-tensioning the belt. I just removed the screws and slid it off the pump. Obviously this did ultimately loosen the belt. Putting it on again will just be a reverse of this process, and as long as the pump is the proper design the belt should have exactly the same tension without the need to adjust the alternator positioning at all.

In cases where the belt tension does not need adjustment, it would seem that this could be a very easy way to accomplish an exact replacement-in-kind with a new belt, if(!) tension adjustment is not needed. I can imagine that as a belt wears and falls deeper into the groove, pulleys need to be tightened, so a new belt might need the pulleys to be loosened a bit. But if you do periodic replacement of belts as a precaution before they become severely worn, you might be able to avoid some headaches by just pulling off the water pump pulley and putting on the new one without adjustment.

Once I removed the pulley I could get a very clear look at the source of the leak. It's definitely losing a drop of coolant every minute or so out the weep hole. I assume that this means the pump's bearings are at end-of-life. Is there any value in rebuilding the current pump, or is it best to just buy a new one?

I'll be calling the Westerbeke dealer to price out a "genuine" replacement, for comparison against the ~$50-70 Indian knockoffs and the $140-170 genuine Kubota part.

I'd still appreciate comments or links to some very basic instructions about how to remove old coolant and replace with new. I'm aware of the need to burp air out of the high points, and actually purchased a radiator pressure tester that could be helpful with this. (I've borrowed one from AutoZone the last few years to do an annual pressure check, but they changed to a different brand that doesn't fit the motor, so I found the compatible one on Amazon:

https://www.amazon.com/gp/product/B0067UE6IY

[KWKloeber]

Note that an improperly tensioned belt can shorten the bearing/seal life.
If the bearing is worn enough you may be able to feel wobble in the shaft when rocked side-side/up-down.

I don't see how a radiator pressure tester will help burp but I'm willing to be convinced? It's  used to pressure test the Hx or other components. .

Why not remove the pump, measure the impeller and order the genuine Kb?  Seems that you're making it more involved than it might need to be?

There's a clicker gauge you can use to check belt tension, in the 101. Or the thumb test.
Haven't needed to tension a B alternator, but a bar or huge screwdriver might work to hold the alt while tightening. Or, there's tools, homemade and commercial spreaders to hold the pulleys apart. Search (google) on the main page - it's in the forum posts.

I've seen folks who rebuild those pumps, but for $70-ish new Kb, why?  It would be a good test though to let us know how long it lasts.

[Jon W]

NAPA auto parts sells a belt tension tool called the cricket. Easy to use and small so easy to store.

[Breakin Away]

I've seen folks who rebuild those pumps, but for $70-ish new Kb, why?  It would be a good test though to let us know how long it lasts.

At $70 it's a no-brainer to go with genuine Kubota. Please let me know who has it for that price (maybe you?), because I haven't found it anywhere near that price. Thanks!

I have answers for your other questions - will explain when I'm back at my computer with a real keyboard.

[KWKloeber]

Whoops. You're right they're about double that I think, I was thinking if the pump for the D850 block that was around 70 from Kb.  IIRC Wb is about 3x the Kb cost.

[rmbrown]

My kubota part was more like $135.

[KWKloeber]

Mike

What p/n?  The pump for the 35 may be more than the one for the D850/950 (m25/xp).

[rmbrown]

I'm crushed to say I threw the packaging away, and I ordered it through a NAPA store (where, ironically the Kubota dealer sent me because "we don't deal with marine engines), but they wanted nearly $100 more for it anyway.  NAPA ordered me the genuine Kubota part as cheap as I could find it online.  I'm all but certain it was 15534-73030, though.  Mine didn't come with the small screw-in nipple on top though and I had to order it separately.

[KWKloeber]

Thx Mike

Doesn't make sense that if the Kb dealer has the p/n it couldn't order the part, regardless of what it's going onto.  I have found tractor/agricultural Kb dealers oftentimes can't order parts for the industrial side, which is a different division.  The cheapest I've seen that pump is 118 + ship.

Ya, I remind folks to keep the hose nipple cus many times it's not on the replacement. Difficult to see, but when I converted my M25 to the separate WH loop, I used a 90 ell, 45 el,  nipple, reducing (increasing) elbow, and a hose barb to change direction that worked better for the hose run.