Fresh Water (Coolant) Impeller?

[SkuffedKeel]

Hello again!

I'm still learning the ins and outs of my 2004 Catalina 350 (first boat) and I've been making sure to keep up with the engine maintenance. This past weekend I did my 100 hour oil/filter and transmission fluid changeout and raw water system inspection including the raw water impeller on the front (salon side) of the engine. Nothing needed to be replaced there, but I mentioned everything I did to my Dad and he seems to think there should be a fresh water (coolant) impeller that needs inspection and replacement. I can't seem to find anything about this in what I've read so far and as I've been working around the engine I haven't seen anything obvious. Am I missing something?

[KenKrawford]

The image below shows the location of the raw water pump. Unfortunately the bolts that have to come off in order to inspect or replace the impeller are facing aftward. You may also have to loosen one or both hose clamps in order to work on the pump. If any of the vanes on the impeller are missing then the it needs replacement. It's also important to find any missing impeller vanes. They may be in the elbow on the discharge end of the pump or in the heat exchanger.
Also, don't forget to close the raw water thru hull (located near the port aft area of the engine) before taking the pump faceplate off. You can access it by removing the "shelf" above the engine in the aft cabin or underneath the mattress access panels. Be sure to open it after you're finished or you'll be repeating the job again real soon!

m35b eng.jpg (151.34 KiB) Viewed 569 times

[wolfe10]

No need to "inspect" the engine coolant pump (driven by the belt). Yes, the raw water pump impeller does need inspection/replacement every couple of years unless high engine usage suggests more often.

Do make sure the engine coolant pump is not leaking-- no different than on any vehicle.

And, yes, changing the coolant every couple of years (no different than any vehicle) is just good preventive maintenance.

[SkuffedKeel]

The image below shows the location of the raw water pump. Unfortunately the bolts that have to come off in order to inspect or replace the impeller are facing aftward. You may also have to loosen one or both hose clamps in order to work on the pump. If any of the vanes on the impeller are missing then the it needs replacement. It's also important to find any missing impeller vanes. They may be in the elbow on the discharge end of the pump or in the heat exchanger.
Also, don't forget to close the raw water thru hull (located near the port aft area of the engine) before taking the pump faceplate off. You can access it by removing the "shelf" above the engine in the aft cabin or underneath the mattress access panels. Be sure to open it after you're finished or you'll be repeating the job again real soon!
m35b eng.jpg

Thank you Ken! In this case it was the fresh water (coolant) system I was concerned about. The raw water side I had figured out although I must have some sort of aftermarket system because mine looks different than stock and is actually really easy to access and inspect the impeller.

SVSenja_Engine.jpg (119.59 KiB) Viewed 564 times

[SkuffedKeel]

No need to "inspect" the engine coolant pump (driven by the belt). Yes, the raw water pump impeller does need inspection/replacement every couple of years unless high engine usage suggests more often.

Do make sure the engine coolant pump is not leaking-- no different than on any vehicle.

And, yes, changing the coolant every couple of years (no different than any vehicle) is just good preventive maintenance.

Thank you Brett, this is the info I was looking for and I appreciate your response!

[nybor]

After yet another Venice to the Dry Tortugas and back (I left with my sailing buddy, but ALMOST came back alone....accidents can happen.....) Anyway, when there was not wind, I started hearing a rasping sound from the water pump. It continued to get louder as time went on. Made it back but want to replace it (engine now has 900 hours).

Has anyone done this? I see two dealers with each quoting $477 for them. However, I keep thinking that the M35B is a Kubota engine.....

thanks

dave

[TBOT422]

Dave,
I believe the M35B is a Kubota V1305. I researched the fresh water pump for it a while back and found a part number 16241-73034. I have never replaced it and can not confirm that is the correct part number. The picture certainly looks correct, and is available on Amazon for $50 . If you go down this route, please let us know if that is a correct part number.

I do see that some similar part numbers have different sized impellers (60mm vs. 70mm). It might be worthwhile to pull the old one and measure it before ordering.

https://www.amazon.com/Friday-Part-1624 ... LrEALw_wcB

[modesid]

I have had very good luck with Kumar Brothers USA this part as I carry two spare.
Cost a few years back $ 106.00
Cheers

[nybor]

THANKS to G&J and "Cheers" (interesting person"s name...). Anyway, ordered the $50 from Amazon and the $80 from Kumar Bros.... Can't believe that Catalina Direct and Toad Marine both offer it for $500. Maybe those are bronze but gosh, I would rather replace them more often. Will report when I remove the current one, weigh it and compare it to the two new ones.

thanks again, Gary and Janet and ..... Cheers.

dave

[modesid]

No the pump is not bronze
The replacement pumps for main engine are just like a car engine for fresh water.
I have found that going the tractor engine Kouboa route saves a ton of money such injectors, gaskets, seals, etc
Good Luck, and Cheers
Winddancer 0011 2002

[nybor]

Great. The marine hardware prices are the same as aviation prices - way way over a reasonable markup. I will report to the troops once I get the tractor parts and check that the impeller is the same diameter as the one on the engine.

THANKS TO ALL

dave

just curious. since a tractor uses a radiator as the heat exchanger, is the raw water pump not part of the engine accessories? I would think that the fresh water pump (the one to circulate the antifreeze) would do the trick alone, since the fan blowing over the radiator core is the "raw water pump".

pps I talked my friend who is a fishing charter cap, and he said the BEST thing he adds to the cooling water is "Water Wetter". On the label it says with a 50/50 antifreeze/water mix, the addition lowers the temp by 8 degrees F. He uses only distilled water (no propylene glycol-based coolant) and this stuff and it lowers it by 15 to 20 degrees on his Cummings diesels...

[wolfe10]

Since a tractor uses a radiator as the heat exchanger, is the raw water pump not part of the engine accessories? I would think that the fresh water pump (the one to circulate the antifreeze) would do the trick alone, since the fan blowing over the radiator core is the "raw water pump".

pps I talked my friend who is a fishing charter cap, and he said the BEST thing he adds to the cooling water is "Water Wetter". On the label it says with a 50/50 antifreeze/water mix, the addition lowers the temp by 8 degrees F. He uses only distilled water (no propylene glycol-based coolant) and this stuff and it lowers it by 15 to 20 degrees on his Cummings diesels...

Correct. The raw water pump/second pump is marine only with the tractor cooling system working basically like on any automobile with the single water pump only.

I would definitely NOT use your friend's advice on distilled water only. 50/50 quality coolant/distilled water will both protect in below freezing temperatures, but also substantially reduce corrosion in the engine and heat exchanger.

BTW, any time the use of a different coolant changes operating temperature, the cooling system is UNDERSIZED. Said another way, the thermostat is wide open and is still not able to control temperature.

[wolfe10]

And, when you refill with new coolant/distilled water, be sure to bleed the air from the fitting on the water heater (highest point in the closed cooling system).

Yes, lots of fun getting down in there!