This is my "Belt and Suspenders" method.
If you are looking for a quick and dirty method, this Isn't It!
If involves removing the Thermostat, draining the block, Flushing with Antifreeze, and Draining again.
The "Bucket and Hose through the Muffs" method works just fine.
This method gets very BAD Reviews when done improperly.
It is imperative that the engine has been drained before flushing. Not Optional!
Remove the Thermostat. Hot Engine or Not, as soon as the cold Antifreeze touches it, it will close.
Place a kiddie pool under the drive to catch the Antifreeze as it comes out the exhaust.
I place a plastic ball valve on the end of a short piece of garden hose.
Prime the hose and then close the valve to hold the prime while you attach it to the muffs.
Priming by mouth suction is doable. Propylene Glycol (PG) is a major ingredient in Nyquil and tastes about the same.
As long as you ingest less than a Pint, it is harmless. It just tastes bad. (Unless you Like Nyquil!)
Place the bucket up high on the back of the boat and run the hose down to the muffs.
When ready to flush, open the valve and then start the engine. Idle speed Only!
The water pump's impeller will suck the Antifreeze into the engine at an impressive rate.
You will need about 6 gallons of Antifreeze.
A 5 gallon bucket will hold about 4 gallons reasonably.
Once the engine is started, dump the other 2 gallons into the bucket quickly.
Start with a cold engine as you will not get any cooling of the exhaust until about 5 gallons have been pumped in. (30-60 Seconds).
Drain the block again and save the Antifreeze for use next year.
This is the "Air Don't Freeze" Part of the process.
Any remaining Antifreeze will have displaced any water in the low spots that didn't completely drain.
The block was designed for automotive use, and was never intended to be100% completely drain-able.
After draining, the old antifreeze can be filtered through an old T-Shirt and saved for use next year.
I have antifreeze going on its third use. I added a Gallon of -200 Last year to strengthen the mix.
It will not even form slush at the -5F of my freezer.
Test a sample of your Antifreeze after flushing by placing a sample in the Freezer.
It may turn solid but you should be able to push a cold Butter Knife into it without much force.
-50F Antifreeze starts freezing at -16F and is a solid, very firm like a snowball, but not as hard as ice, at 0F.
If temperature below 0F are possible in your area, then the common -50F Antifreeze may not be sufficient if it has been diluted by any water remaining in the drained block. It is available in -50, -60 -100, and full strength -200F concentrations.
PG (Pink) Antifreeze is available at a discount this time of year. A case of 6 gallons can be had for ~$25.
Be wary of the antifreeze sold for under $3 a gallon. It is often Alcohol based. Be sure you get PG Antifreeze.
With Alcohol Antifreeze, over time, the alcohol evaporates leaving only the water. Bad.
With PG Antifreeze, the Water evaporates first, leaving a stronger mix of PG. Very Good!
