ok,read a few things posted on the subject of winterizing engines...
this is how we do it at "jimmy's marine service llc"......
inboard engines-this includes stern drive engines...
run that engine on fresh water-i use the "salt a way" flush while running the engine.get it to temp,then shut it down,change the oil and the oil filter-pull the block drain plugs{raw water cooled only} drain the block and pull the manifold drains as well.refill the oil and install the new filter.pull the plugs and do a compression test-look at the plugs closley-look for really white plug or plugs with rust stains-this means water is entering the cylinder-trouble...the compression of all the cylinders should be even + or - 10%-if they vary more than that...we got some issues...
now reinstall the drain plugs and the spark plugs.use a little grease on the drain plugs-this will avoid them getting siezed in place...
now here's where it gets tricky-i use a winterization tank,it has a bilge pump in it to pump the non toxic antifreeze into the engine,via the water pump...you can use a bucket with a thru hull drilled into the bottom of it-allow the sealer to dry first-connect a hose to that bucket and the other end is connected "ear muffs" for a stern drive engine,or for an inboard engine,the hose is put inside of the intake hose for the sea water pump.start the engine and give it the antifreeze while you're spraying fogging oil into the carb-when the antifreeze shows up in the exhaust-it has filled the engine and the exhaust system,when the antifreeze is gone,shut down the engine !!
spray the engine with a moisture displacing spray-i use "corrosion block" or "crc"-these are the only things i'm aware of that actually neutralizes salt-i hate wd-40 and never use it !!
if you've got a stern drive-it needs to be removed,to be service properly.by removing it,this is the only way to check the drive shaft bellow for sea water intrusion.change the oil in the drive and lube the u-joints as well as the gimbal bearing.when changing the gear oil-if it appears to be "milky" you've got a problem-water intrusion-needs to be pressure/vacumn tested to determine where the leak is...don't forget to pull the prop to lube the shaft...
inboards-change the gear oil too...don't forget to cover the exhaust on the transom-use old towells....
what not to do.....DON'T USE REGULAR ANTIFREEZE-EVER !!!! DON"T leave the block and the manifolds "dry" this will cause oxidation-which will lead to clogged exhaust manifolds and other fun things-if these are filled with nontoxic antifreeze-there is an absense of air-therefore no oxidation....makes sense huh ???
remember....any issues found now should be addressed now-this avoids a delay in getting the boat into the water in the spring!!
last point....fuel tanks and systems-if the tank is more than 10rs old-be careful !!!! aluminum fuel tanks in a salt water application,have a finite life span-approx 10yrs-is the accepted norm !!! remember this !! every year i get a few customers who-have mysteriously lost their fuel....hmmmmm..also i've had a few customers who picked up their boats,to have them leak fuel in their yard over the winter-so word to the wise....be aware of this !!!
by taking the above steps-you've done a good job "puttin' 'er to bed" !!!
if you guys need a little advice drop me a line jimmysmarineservice@comcast.net i'll be glad to help you out !!