raw water pump impeller service on 72 chris craft commander, 300hp/ 427 engines, OMG

ok, 1st off, is the raw water pump the pump on top of the motor or the one on the bottom, i know the answer but i am praying i am wrong, how the hell do you get to these pumps to servie them? the starboard motor is bad enough but the port engine has the steering mechanisim right in front of it with no visual whatsoever. how the hell was this serviced back in the day

stang32 said:

ok, 1st off, is the raw water pump the pump on top of the Engine or the one on the bottom, i know the answer but i am praying i am wrong, how the hell do you get to these pumps to servie them? the starboard motor is bad enough but the port engine has the steering mechanisim right in front of it with no visual whatsoever. how the hell was this serviced back in the day

Click to expand...

The cast iron body pump that is fastened to the front of the Engine (via four bolts) is the Engine Coolant Circulating pump..... aka Circ Pump.
On a 1972 Engine, this will be V-belt driven.

I am not familiar with the 1972 ChrisCraft Commander 427 engines. However, the seawater pump will be either V-belt driven or crankshaft driven.
It will likely have two large hoses connected...... one feeding into and one leading out of it.


Inside of the Seawater Pump will be a flexible vane impeller.
These impellers should be removed for the winter lay-up, and re-installed prior to recommissioning in Spring time.
Reason: at any given time, three or four vanes are folded over against the impeller cam. If left static for long periods, this will cause those vanes to take what we call a "set".
These vanes need to maintain resiliency.


Pictures would be helpful.







.

hereis a link to the lower pump, below the crankshaft

https://photos.app.goo.gl/kYTDBN1Q64XYTchX8

and here is a link to the photos of the pump above the intake


https://photos.app.goo.gl/4h8g9jWu4o6UBhmm9

thanks for the reply

Paul, no offense..... but I'm getting dizzy just looking at the photos! :rolleyes: What a complex system!

Owners of these belt-driven Sherwood seawater pump systems almost always defer impeller maintenance due to the difficulty of accessing the impeller. Then they wonder why they have over-heating issues!

Not too long after this era, the Marine industry began simplifying the raw water cooling systems. The Jabsco, Johnson and Sherwood crankshaft pumps became popular, and still are today!
If this was my boat, I would remove all of that old and outdated stuff.
I would go back together with Johnson F6B-9 crankshaft mounted pumps.
I would update the T-stat housing and would re-route the hoses.

You would end up with a much simpler system with much easier access to the impellers.
Also, there is no belt-tension side load with the crankshaft pump, meaning that bearing life will be extended.
Remove four cover screws..... and there's the impeller!



Examples only...... some of these are SBC. BBC is very similar.

View attachment 18422

View attachment 18423

View attachment 18424


Perhaps Food for Thought!



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whether you opt to change the raw water pump, the rest of the pulleys will need to be cleaned up....if they are left as is, you belts will erode and start slipping....if it continues, you will run out of adjustment.

To answer your last question, by the hour.....

makomark said:

To answer your last question, by the hour.....

Click to expand...

LOL, yeah i guess so. i am doing the same but OMG, i just want to take a sawzall to the interior wall panel and cut in an access hole

so, am i correct in saying the raw waterpump is the lower one?

yes, you should be able to follow the suction hose back to a thru hull, hopefully by way of a strainer.....

In my younger days back in the shop, we had a couple engine installs that required removing (partially, just elevating for clearance) the engine to change the oil filter - block mounted....the speculation was a previous owner had an issue with the remote setup and opted to eliminate it vs replacing it.....

stang32 said:

ok, 1st off, is the raw water pump the pump on top of the motor or the one on the bottom, i know the answer but i am praying i am wrong, how the hell do you get to these pumps to servie them? the starboard motor is bad enough but the port engine has the steering mechanisim right in front of it with no visual whatsoever. how the hell was this serviced back in the day

Click to expand...

Is the motor backwards. The real back of the motor is shaped like a house

Go to chris craft-parts they have a lot of old chris parts

georgesboats said:

Is the Engine backwards. The real back of the Engine is shaped like a house

Click to expand...

In marine terms, this would be referred to as a "Flywheel Forward" installation!


Stang...... seriously.... please go back and re-read my post #4.
This job would be quite an undertaking, but you would do it only once and you would not need to look back.

My images in post #4 are not working.
Let's try it again.
These are examples ONLY: