I run 2 gallons of AF (pink) through my 2GM20F. Some of my friends do 1 gallon…but figure $5 is not too much to waste to guarantee my engine doesn’t get damaged.
For the head, you need to pump the AF through the pump, not just dump in the bowl and pump it out. I remove the hose from my strainer and stick that in a gallon jug…then pump away. Less than a gallon needed.
I also run about 2 gallons through my potable water system. Make sure to drain the water out of the tank(s) first. I don’t like to put AF in my water tank, so I pull the hose off the outlet and put that in a bucket of AF. Also, I bypass my water heater, otherwise you will fill the water heater with AF. Turn the water pump on… I open each faucet (first hot, then cold) ant each faucet until pink stuff runs out. Don’t forget any anchor wash or outdoor shower faucets. That should be good .
Ladtly, I put some AF in my bilge in case I get any water in the bilge. I also turn the bilge pump on to pump some AF through the bilge hose.
I think that covers what I do.
Greg