What kind of drive

alpha 1

Does your thermostat housing have the check balls in it? if so, one could be sticking, hurting water flow to the exhaust.

Are the rubber through hull exhaust hoses getting hot after a run, too hot to touch, and feeling soft?

Is most of the steam coming from the right (driver side) exhaust?

Most merc engines has a screen on the inlet to the oilcooler. I guess it is there to stop impeller blades and the like to enter the engine.

The steam is pretty overal. I checked the check balls they move freely but did notice that on one side the metal isn't straight anymore its more like / so the ball never completly seals it. Don't know if that could do anything.
as far as the exhaust rubber. it does get a little bit soft. Sometimes the motor runs up to like 180 I don't know whats going on as everything is nice and clear with a new pump in the drive.

is there a way to check flow at specific problem points?

my motor has the big buliky thermostat housing with the check balls. When I feel those 2 lines they are really cool, but when I feel the bottom 2 they are almost two hot to touch. I am at a loss here "frustration has set in" what will taking the thermostat out do?

Im posting some pictures of my problem after I jsut changed the thermostat housing so what we have is

new impeller
new water pump
new thermostat houseing wiht new check balls

the water temp is perfect at 145 during idle and throttle I can keep my hand on the exhaust water for a few seconds before it gets to hot...what do you think steam or smoke?? first 2 at idle 700 next 2 at 1300

1300

Does not look like enuff water flowing....I would say that it was steam...I would be suspect of the impeller...new or not maybe it did not go back together right....Housing could be scored ...something stupied like the seal around the copper pipe. Also I have had the pipe that goes thru the transom leak. It can corrode. pull up a merc diagram you could see it leaking on the hose with the drive turned to the right.

That definitely looks like steam caused by low water flow. Been there. Since it is both exhaust pipes the problem should be in the section before the water is split up two paths. I am not familiar with the alpha drive but are there any screens, hoses or seals/o-rings down in the drive that can create a problem?

I'll keep checking but its flowing alot of water...its all over the driveway...its shooting out alot