Re: oil change 5.7 350 MPI
There should be a drain hose attached to your boat's drain plug. Or it may be secured high on the motor somewhere. Route it thru the boat's drain hole and drain the oil outside of the boat. I add about a tsp of 2-stroke oil and 1 tsp of fuel stabilizer into the spin-on fuel filter. Make sure it's fairly full of gas before spinning it back on. If the electric fuel pump runs too long wihtout fuel, it can burn out.
Merc has a winterizing package this year that includes fluids and a DVD that takes you thru the steps. It would be a very wise investment for first-timers.
