Outboard orientation during static flushing

[Frank O]

For some time now I've been religiously flushing the cooling system of my 1994 Mercury 3.0L Offshore 225-HP carb 2-stroke outboard at the end of each day on the water. The boat is kept in a slip. My routine has been to raise the engine so the prop is out of the water, connect a hose to the fitting next to the telltale, run water for a bit and then switch to Salt Away. (I.e. this is "static flushing" with the engine not running, not done with "earmuffs.")

Recently I discovered that rinse water appears to be entering the exhaust ports and getting into the power head during this process. My owner's manual and Merc shop manual don't say anything about it, but I noticed this passage in a newly acquired Clymer book on my outboard, under the section on flushing the cooling system:

"Keep the outboard in the vertical (normal operating) position to allow all water to drain from the drive shaft housing. If this is not done, water can enter the power head through the exhaust ports."

What is the usual way to flush an outboard when the boat is kept in the water in a slip? If I do it with the lower unit in the water, it seems as though there could be a tendency for some saltwater to remain in the lower unit when the engine is finally tilted up for storage.

 

[Chris1956]

Re: Outboard orientation during static flushing

Frank, When i flush my 150HP Johnny in it's saltwater slip, I run the motor in the verticle position, with the hose attached. After I have run it and am sure the thermostats opened, I shut off the motor and let it flush a bit more. I then disconnect the hose and tilt it up as the fresh water drains. I believe this gets the vast majority of the salt out of it.

I really do not think you can flush all the motor, when the boat is in it's slip, without tilting it up and risking water in thru the exhaust port. The method I use should flush all but the thru hub exhaust housing and the waterpump.