Just got a boat with 525's. The mechanic at the dealer showed me 2 blue plugs on each moter. They screw out amd that is supposed to winterize the boat. It does not have the pump like the others. Of course I will check the antifreeze also. Sound right?

run anti freeze thru the entire raw water side. cheap insurance
heat up the motors and make sure the thermostats let the antifreeze run thru the entire system

they are close cooling so the motors themselves are safe,,,,, i would drain the water and run some antifreeze through anyway just to be safe with the heat exchanger,,,, cheap ins

x2

dont forget the blue plug on the fuel chiller and power steering cooler

Check the closed cooling antifreeze to make sure its good to zero degrees

Exact same procedure/thought process as the 496.

Even if your engine has an air pressure system to force the water out of the engine, it's NOT good enough for FULL winterization.

Just draining the water out of a 525EFI is NOT good enough.

See this thread:
http://www.offshoreonly.com/forums/g...ing-496-a.html

The tstats are on the closed cooling side, so that is not necessary. But, mine are always warm before I fill them with antifreeze anyway because I change the oil right before I fill them up. And I use the good stuff...Banfrost. Not the cheap pink stuff.

And there are alot more than two blue plugs on these motors. There are two on each header rail alone.

OK - I am going to have a mechanic winterize the boat this winter to understand these engines. Just to educate myself - there are two plugs on the headers, one on fuel chiller and power steering cooler. Any others?

yes you are right ....6 plug total