First off there is no simple winterization technique. It requires some expertise (amateur is OK) and a clear understanding of the purpose you are trying to achieve.
I am going to weigh in here with my thoughts...If you are not 100% positive about whether or not your motor is protected then either don't do it yourself or figure it out. Make sure you understand how your system works as a whole and what you are doing to protect it. Ask yourself if it makes sense..... Follow all the hoses and look for water traps (ie the oil coooler on the 7.4 Gi)
Marinas use the "suck up" method because it's fast and each marina has their own methodology PLUS they are insured if something happens to go wrong. You are not insured if you do it yourself. A new motor is very costly
Borchik wrote:
Marine tstat housings have bypasses in them. Once you see antifreeze coming out at the transom and through the prop housing then the water is though all passageways.
I disagree with this statement. I just had the thermostat housing apart on my 1989 Merc's and there definitely is no bypass. The Alpha one pump circulates above the tstat and out the manifolds...Once the Tstat opens then the raw water gets sucked in by the engine circulator. I saw no evidence of a bypass.
I do agree with the statement below. Cheap piece of mind if you aren't 100% sure of yourself.
Or, if you are really concerned, let a marina do it. My place charges about $170 for a basic winterize which also changes your gear lube, stabilizes your fuel and changes the fuel filter. Our work is insured, in the 15 years of winterizing this method we have never had a single issue and we average about 400 winterizes a season. If it broke it would be warrantied. Just some food for thought.