another warm engine

[Calcutta]

If you aren't seeing the discoloration on the 'glass elbows, you have not lost your diffuser plate, as I had...h'ever, if there were any blockages in the plate (primarily adrift, spent zincs), it would effect the flow of the discharge water at speed. The gear cooler is just upstream from the exhaust elbow and I seem to always break off my old zincs when I go to remove/renew them from the gear cooler.

The plate is like a very large flat washer, the center opening allows the exhaust gas out. The diffuser basically consists of holes appx 1/4" diameter, pressed all around the diameter of the plate. This is where the h2o when under pressure, gets its lift. It doesn't take much to block a portion of that surface area.

If you call you local CAT dealer, he will provide you w/great diagrams of the exhaust elbow system, which will explain it better.

[jim rosenthal]

Thanks, Gregg. On my boat, I can pull apart the top section of the exhaust system if we remove the electronics box on the aft top of the engine, and look into the diffuser plate area. I will ask the CAT dealer, T&S, about this. When I fired her up, both engines ran at the appropriate temp, but the water flow through the stbd engine seemed more brisk at idle. The trans cooler WAS clogged- there were some old zinc pieces and also lots of crap in the cooler.
I need to be more aggressive about maintenance on the seawater side of the system. This winter, if not sooner, I will pull both exhausts off altogether and go through them. Clearly flushing and winterizing them is not enough.