Once, I had a piece of impeller rubber stuck in that little chamber next to the transom that your hose from the pump connects too.

I guess I should pull the manifolds. Unfortunately I might have to pull the motor to pull the manifolds. These motors are 572 tall decks and there is not 1/16 clearance between manifolds . Steam did get worse as motors got hotter. But it wasnt like a mosquito truck haha. These gils are very old with the old black risers. Impellers were fine in the water pump.
I have transmissions in this boat I guess trans comes out when motor is pulled ? just asking new to me .

I guess your plugs would be super clean if water was leaking into the cylinders ? Mine were not. Still had good old carbon on them .

correct thats why I tend to belive its not a water ingestion issue but something else like not enough water to cool the headers ect, the fact that you stated you went up to 130 with no thermostat in less then 2min also leads me to belive the same thing, check for water flow issues ...........

Check all the water hoses and coolers. If an old impeller came apart pieces of rubber may be restricting your water flow. Might be why temps are going up quick.

Thanks for your comments .When I pulled the water pump last night , I did notice alot of crap on the back side of the housing , The power steering cooler is 6 inches away . I sure would hate to pull a motor for nothing . The cooler could be corroded. But the slow start makes me think ingestion but I never have to pull plugs to start . This motor does have an old starter .New starter on other motor.

Well I just got an email from the guy that owned the boat before me. He thinks Im chasing a non existant problem . A few more things to check and maybe it is. But the darn thing steams !!!!! And its coming from somewhere .....He said he never had any problems. I believe him . Im stumped ...Im going to purge all the lines and strainers and coolers. Then Im going for a boat ride ..........................

try back flushing it and see what comes out

is it a bravo boat ? The water hose that connects to the drive bell housing and goes through the transom somtimes with age closes off and restricts the flow of water to the engine. a friend of mine has a 242ls formula with a 330hp with a bravo had a steaming problem and that was the problem. common on older salt water used bravo boats.

No, #4 speedmasters with off shore pickups. I plan to check all cooling lines this weekend. Runs to good to be internal, I hope !