I got a Mercruiser 4.3 MPI and at 4,200 RPM plus I start getting water in the base and pushes out the dipstick tube. Below 4,000 RPM everything seems to be fine. I was wondering if anyone got any suggestions. I found a hose that comes from the thermostat housing and goes to the bottom of the exhaust manifold plugged with rust and flakes of rust as well. I cleaned that out and it is still the same. I hope that there is someone who can point me in the right direction.
