Suzuki 2 HP overheating

[HeadlakesuzukiDT2]

I have a Suzuki 2 HP 1900 or 1991(not sure) but it was given to me. it is overheating about 15 minutes of running.
I have changed the water impeller, pulled off the power head and the water jackets at the bottom of the power head are fine, (no obstructions) I then pulled off he head, removed the gasket to gain access to the water jacket around the cylinder. Again no issue to be worried about. I am in a waiting game getting a head gasket, it is on order but will take a week.
Has anyone else run into this issue, and if so did you get it corrected and if so what was the issue.

 

[greenbush future]

Do you have a good strong "tell tale" water stream (not sure Suzuki has this)
How do you know the water pump (impeller) is pumping? Could the impeller be in backwards?

 

[HeadlakesuzukiDT2]

Nope the impeller is installed correctly.
I it don't have a tell tale water stream. it is older and steam and water mist comes out of the two holes in the lower unit top end just below the power head.