Impeller Veins Missing Inside Raw Water Cooled 5411

[fox9988]

Solved: I read on the internet that a $25 Mercury-Mercruiser 47594 Thermostat 143F would fit the Universal 5411 vs the $109 OEM Z2707, just drill the two 1/8" holes on the flange for exhaust cooling flow. It did fit, physically.
The OEM thermostat has a nipple on the bottom. When the thermostat opens, the nipple stops flow into the recirculation orifice, forcing flow into the muffler/exhaust orifice. The $25 thermostat doesn't, allowing endless recirculation of the coolant water.

https://www.catalinadirect.com/shop-...l-diesel-5411/

https://www.wholesalemarine.com/merc...ostat-143.html

Also, my OEM thermostat does need oriented correctly to allow flow through the 1/8"holes.
Thanks for the replies. I'm learning.

[hpeer]

Cool…..er!

[Kerryf]

A very experienced captain I once worked for made me find every piece and match then to the impellor like a jigsaw. The bigger pieces will not go through the heat exchanger or/and the exhaust injection nozzles. If you don't clear out all these areas in the calm of the dock they will come and call out to you some dirty day when you need 100% engine load to get off a lee shore and your engine overheats.

[Xlantic]

My ancient Onan generator had low exhaust water flow.

One day I took off the a pipe elbow coming out of the pump and found half a dozen broken vanes and pieces, jammed in the corner of the elbow.

I had never had broken impellers in the five years i had the boat so they had to have been there at least that long, and possibly much longer.

So, I suggest you take a good look inside the pipe fittings, particularly the elbows.

[MVDarlin]

It is essential you follow the water path until you find and remove the broken impeller blades. !