Sydwayz

iTrader: (1)

Yep, that's exactly what I do.
Run it up to temp.
Change the oil.
Run it up to temp again.
Pump and Drain all the freeze plugs-

IIRC, there are 5 blue freeze plugs on each motor.
1 on each side of block
2 on SWP assembly
1 on back of oil cooler (far aft-port side of motor)

Run 3 gallons of AF through the motor.
Shut down and pull fuel/water separator-
Fill FW separator 1/2 full of 2-stroke oil & reinstall.
Run 3 motor gallons of AF through the motor.
Coat with WD-40
That's it.

As for your impeller, it is likely that it is damaged. The AF is slightly thicker than water and hence it will be harder to pull up the outdrive.

BUT, I don't do mine with muffs. I HATE running on muffs. I installed T-fittings directly infront of my SWP so my garden hose injects water right infront of the impellor. When you turn the water hose on, it flushes from the SWP backwards out the drive.
When you tun the engine on, it sucks the water directly into the SWP. No tape or muffs needed.

Bosco

x- mercury makes a nose cone water pick up you can plumb with a set of the typical ear muffs. eliminate any b.s with tape and worry and give the drive all the water it can stand.
never run it without water you will cook the pump in seconds not minutes.
winterization consists of removong all the raw water from heat exchanger and riser/manifold combo. these motors have blue drains which will eliminate all those freez concerns. the closed part of the system should be filled with anti-freeze.
lastly, i fog with marvel mystery oil. run the motor to temp, and gradually introduce a spray into the air intake. trust me the motor will gobble it down and stall. thats all..............
in the spring she will smoke on start up but clear up rapidly. put in new plugs and enjoy!
Bosco

specialk

Even the muff on the front wont suck up water thru mine. I have a seastrainer on my boat so it is simple to pop off the cap and run the hose inside it. Also, If you are in a freezing climate, dont forget to check the coolant in the closed cooling portion to make certain it is good for cold temps. Dont be afraid to splash some antifreeze in the bilge at the bilge pump in case there is any water inside it.