2004 2000 sr3 overheating

[Bitofhog]

My 2004 2000 sr3 is overheating. It has the 5.0 MerCruiser engine btw. My first thought was the impeller in the outdrive. I replaced that and it has made no difference. Assuming I replaced the outdrive impeller correctly, what is the next place to look? My friend said there are 2 impellers. A second one near the water pump. But I have seen this one. Could the thermostat cause this? Is there a second impeller to change? Is there a way to test the impeller I just changed out?

Sad boater.

[mmwjr]

First you did not say what drive you have but since you said you changed the drive impeller it must be an Alpha.

Try removing the hose at the t-stat housing that comes from the transom assembly, should be the large hose on the port side. Start the engine to see if water is pumping out. If you have flow the impeller in the drive is working.

Only one impeller but the is a circulating water pump on the engine. Yes it could be the t-stat or clogged exhaust manifolds or elbows.

I would use a IR temp sensor and measure the t-stat housing and exhaust to see what everything is running at.