LouC wrote:
You were lucky...because with raw water cooling, if the thermostat does not open up all the way, what happens is the water in the block cannot exit. So you can have manifolds full of AF and the block with all water or a weak AF/water mix. If you drain the block first then this is not a concern. None of the I/O manufacturers ever recommended this method, this was something marinas did to winterize hundreds of boats fast, but they have running troughs that re-circulate the AF to keep it hot enough to make sure the stat opens. This method does work fine if the engine has closed cooling.
Anyone who has an I/O really should learn to drain the engine. Just like you learn to dock a boat and how to launch and load it. BTW, you will learn the draining part much faster than the docking part. Its not hard but if you miss a drain plug its going to cost you if you do have a hard freeze.
Sorry. I Forgot to mention that before running antifreeze I run my engine for about 10-15min. For me its just easier than trying to be a contortionist in the engine bay removing those two water pump hoses.