2000 82 MPI low wot rpm and steam from exhaust

"Hello,
I have twin 8.2 MPIs

"Hello,
I have twin 8.2 MPIs with 450 hrs on them. I have alot of steam coming from the exhaust on both engines. Even at idle after the engines warm up, there is abnormal amount of steam from the exhaust. At high rpms, it billows out. It is not smoke.
I have checked the temps on the engine with a laser temp guage. The coolant is about 160 F and the raw water discharge is about 100-110 F so I am not sure what is causing the steam. The only temp I could find that was high was the top of the manifold where it joins the riser. That temp is about 190 and the rest of the manifold is about 170.
In addition, last season I was able to get 4200 rpm at wide open throttle. This year 3500-3800 is max on both engines. I don't know if the problems are related.
Earlier this year, I thought the engines were overheating so I replaced the exhaust manifolds and risers on both engines and replaced all the spark plugs and wires.
Any ideas on what is causing 1 or both of these symptoms? Thanks for any advice."

"The risers are running WAY to

"The risers are running WAY too hot. Check to see if the water is flowing properly through them.


On the loss of rpms, you might have a dirty bottom, or the props got nicked a bit.

JEff"