7.4 mercruiser winterizing

crquisto · Post by **crquisto** » November 9th, 2015, 10:23 pm

Does anyone know how many gallons of antifreeze it takes to winterize each engine's seawater side from the thru-hull to the exhaust on my 2000 405 with 7.4 Mercruisers?

feeez · Post by **feeez** » November 9th, 2015, 11:06 pm

crquisto wrote:Does anyone know how many gallons of antifreeze it takes to winterize each engine's seawater side from the thru-hull to the exhaust on my 2000 405 with 7.4 Mercruisers?

If I understand this correctly you keep feeding it until the antifreeze comes out the exhaust. My 350 MPI's take around 4 gallons before the pink comes out. It will be more if one of your engines routes water to your water heater while underway.

Lyndon670 · Post by **Lyndon670** » November 10th, 2015, 6:26 pm

Yep, once the pink is pumping out of your exhaust - mission accomplished.

crquisto · Post by **crquisto** » April 25th, 2016, 2:55 pm

My 2000 406 book says to fill a 5 gallon bucket with antifreeze and run it all through. Si cs you can't see the exhaust color with the boat in the water, that's what I do and have had no problems

7.4 mercruiser winterizing

7.4 mercruiser winterizing

Re: 7.4 mercruiser winterizing

Re: 7.4 mercruiser winterizing

Re: 7.4 mercruiser winterizing