1985 50 HP Mercury won't pump water, does this motor have thermostat?

After lots of searching I can't find the answer to my question, so I'll start a new thread. Fired up my 1985 Merc 50 hp with the garden hose muffs for the first time this year and won't pump any water. SN 6587637, 4 cyl. I can blow compressed air from inlet to outlet and outlet to inlet, and get some air coming both ways. Hook up the hose, start the engine, rev it up a bit and nothing. I let it run about a minute and the motor is getting hot enough I don't want to run it any longer.

I also tried the bucket to make sure I was getting water in the right places, filled over lower unit and still nothing coming out when running, not even a drop.

I can't find a thermostat on this motor but some people say it has one, does anyone have a parts diagram or can tell me if this motor has a thermostat?

I'm planning to drop the lower unit and inspect the impeller tonight but want to make sure there isn't another simple problem before I do that. Thanks for the help guys, this site is full of great info!

Re: 1985 50 HP Mercury won't pump water, does this motor have thermostat?

I thought I would go ahead and post a reply so others can reference this information. I pulled the lower unit and removed the water pump top cover, the impeller had most of the fins broken off or curled over, there was even some rubber that looked like it got hot and melted in the bottom of the cup. It was pumping good water when I put it away last fall, I'm not sure what happened between fall and spring but I have some parts ordered to fix the pump and hopefully I'll be up and running again.