I have a 2000 Mercury 50horsepower 2-stroke outboard engine. I have replaced the thermostat and water pump. The engine quickly overheats. Some water does come out the outlet tube, but not as much as used to when it was new. I need to know what else to check to diagnose this problem. Any suggestions would be helpful, thanks.

Cheez.
Nobody answered your posted question about your overheating 50hp Merc.
Did you figure it out?
I have a similar problem... not as much volume of water on the output tube... overheating... I just disasembled the lower unit and the impeller looks OK.
Hmm.
Any help would be appreciated.
Jimmy Young
[email protected]

I had a similar problem. Your might want to try replacing the water pump housing, they sometimes get scored and don't seal the waterpump. And all of you gaskets in that area. There is also a rubber tube that sometimes get misaligned when reinstalling the lower unit. Check that lower unit isn't clogged with mud diver. Where the water pees out of the motor sometimes gets clogged. Remove the hose and run a piece of wire or mono through it to unclogg. These things should fix your problem. Has worked for me in the past