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If this was my boat, I would remove all of that old and outdated stuff.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.
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Perhaps Food for Thought!
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