Boat won't start, how to drain to winterize

[Makeithappen]

I went to winterize my boat today, last minute as usual. Boat wouldn't start but eventually did but I ran in long enough to let the gas treatment go through then shut it off and set up the new antifreeze drain thing I bought and went to go start the engine and it wouldn't start. I've had to change spark plugs every year, initially it was at the beggining now its at the end of the season when it doesn't run for a month or so. Anyways, it's a 99 searay 180 with a mercicruiser 3.0 I/o. I found two drain plugs on the right side and opened them both up, turned it over a couple times and it obviously doesn't start. I drove around a couple blocks and from my house, down a fairly long block I can tell alot of water came out down the entire block kind of up a hill and down. I'm not sure if this is enough. I've ran antifreeze through it the last 3 years and it's seems to be fine, including the -50 spell we had last winter. Please let me know if there's anything else I should do. We're dipping into the 20s everynight from here on out. Thanks for the quick responses.

 

[Bt Doctur]

If you removed the block and manifold drains and you did check to make sure they were draining by probing the openings your fine. If you want to add AF, simply remove the large hose from the therm and pour the AF into the hose until it comes out the therm housing. Same for the manifold, remove from therm housing and pour it into the hose until it comes out the exaust

 

[Howard Sterndrive]

just open the block and manifold drains, let the water out - poke with wire to clear rust - remove lower hose to water pump, lower the end to drain the cup or so of water out, reinstall- . no antifreeze or driving around required.