Here it is and it is for a 4 cylinder. There is only a small differences for v6 and v8 and closed cooling.

How to winterize an inboard/outboard marine engine only. The water system for a sink or toilet is something else and must also be done.

This is the way I have been doing it for almost 20 years and NEVER had a failure.

You may or may not agree but this my way.


Have 1 gallon of RV antifreeze, Stabil Gas stabilizer, Pliers, 5/16 nut driver, water hose removal tool. Fogging spray is optional. If a salt water boat have a spray can of the protectant spray to coat the engine area and all moving parts.


  1. Hook up muffs to outdrive and have outdrive down.
  2. Pour proper amount of Stabil into gas tank.
  3. Get in boat and start engine. Let run for 15 – 20 minutes.
  4. If fogging is desired remove flame arrestor and spray fogging agent into carb during the last 3-5 minutes of running before shutting the engine off. I do not fog my engine but have done it upon a customer’s request.
  5. Pull/remove the engine block and manifold drain plugs and poke any rust/ residue out until pure water comes out.
  6. While water is draining out of pulled drained plugs (this is for a 4 cylinder raw water not closed cooling) remove the large hose at the thermostat housing, remove the hose that feeds the thermostat housing from the outdrive at the thermostat housing ( raw water), remove the short hose from the manifold to the thermostat housing AT the thermostat housing.
  7. After the block and manifold is done draining put all plugs back in place.
  8. Pour ½ of the gallon of rv antifreeze into large hose, this will go directly into the engine block. Reattach the hose and clamp at this time.
  9. Pour ½ of remaining rv antifreeze into the small short hose to the manifold. Reattach this hose at this time.
  10. Pour the remaining rv antifreeze into the long hose from the outdrive this will flush any water left in the incoming system including a power steering cooler if in place. When done reattach this hose.
  11. Trim outdrive up if desired or leave down for winter.
  12. Disconnect battery positive only if leaving battery in boat otherwise remove battery at this time.

As far as I am concerned you are done for this year.

All oil changes and service is done in the spring so you know the state everything is in. This is how I do my own boat and all is well for the last 14 years.

Comments from GuyEdit

  • I pour the fuel preservative in before my last fill up so it mixes well in the fuel.
  • I change the engine oil and filter after its warm. Then I fog the engine after a minute of running the fresh oil in the engine. Too many acids and moisture in the old oil to leave over the winter.
  • Leave the OD in the down position or the bellows will take a set in the wrong position and cause a premature failure.
  • Drain the OD oil and refill if there is no water in it. Repair it now if water is found.