Anyone tried it? I have a question in on their web site but they don't seem
to want to answer it.

Let me poise the question to the group -

I have a 50 hp fresh water cooled diesel that is beginning to run hot. The
engine temp seems to be creeping up to 200 F at cruising speed with salt
water temps in the 60's. Used to run at 180-185 with water temps of 80+.
Water flow out the back seems less then expected and has been going down
over the years even with a new raw water impeller-pump.

Without pulling the heat exchanger, exhaust elbow, and hydro lift out can
Marsolve clean up the system? Marsolve is $20 a gallon and I am willing to
pay vs having to pull the heat exchanger and elbow. (need to pull the heat
exchanger to get enough room to get the elbow. In fact I might need to pull
the exhaust manifold)