How to Winterize Mercruiser 8.1L 496 Sterndrive Marine Engines

Boat winterization is something that many Boat Owners choose to perform on their own. At www.perfprotec... we provide a complete library of technical articles and videos aimed at helping the Do-it-Yourself boat owner to keep their ownership costs as low as possible.
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Video Timeline
Overview - 0:01 - 0:39
Treating the Fuel for Storage - 0:40 - 1:30
Removing the Propeller - 1:31 - 3:27
Draining the Gear Lube - 3:30 - 4:42
Draining the Sea Water from the Engine - 4:43 - 8:40
Changing the Engine Oil - 8:42 - 13:29
Refilling the Gear Lube - 13:38 - 15:14
Running the Engine on Propylene Glycol - 15:15 - 15:59
Recheck Oil Levels - 16:00 - 17:05
Labeling the Engine that Winterization is Complete - 17:06 - 17:54
Reinstalling the Propellers - 17:55 - 18:56
Battery Storage - 18:57 - 19:46
Engine Specifications - 19:47 - 20:00

[@EmilWester]

great vid! just got me one of these engines and was wondering on how to do it. -much appreciated!

[@ramtruck1734]

Forgot one thing, you should pull the air pressure Valve to release the ACTUATOR ASSEMBLY before starting up engine to add antifreeze or it will all drain out.

[@surveyme301]

Great video. One thing don't forget to check the fresh water cooling side antifreeze to make sure it is still 50/50. Had a customer lose an engine because he did not check it, cracked the block.

[@PerfprotechMarineProducts]

Mike Whitten That is an interesting issue that we have never experienced in over 50 combined years servicing boats. How did the antifreeze get diluted?

[@surveyme301]

Previous overheat/coolant loss. Added lake water and forgot to readjust coolant the mixture.

[@MarkSchuster-ym3iy]

Have you considered sending both props to blades Princeton WISCONSIN. He worked for Mercury racing years ago.now his only business I’d balancing racing props. He did a beautiful job on mine

[@KickRocksClowns]

Great video! Would love to see an impeller change performed while the engine is mounted. Looking to do mine but access is ridiculously limited. Every video I've seen has the engine on a jack or stand.

[@thomaspeterson3582]

Would like to see a video on flushing antifreeze system!

[@quiksilva34]

Awesome video! I know it’s old but did you fog the engine?

[@Matthew-hi5ud]

Great video

[@kentgregory3299]

Great video. I just purchased a boat with a 496 mag. 2005 mercruiser. Are there no drain plugs to pull? My space is tight and it’s hard to see. I need to be certain. This seems too easy, but encouraging. Thanks. Edit: Sorry, plugs in regard to draining the cooling sea water.

[@topdjcom]

Also if it has the cool fuel system with spin on fuel water separator i replace both.

[@thomaspeterson3582]

You have a closed system with antifreeze. Why the need to run antifreeze back thru the cooler system that you just drained?

[@dnail888]

Exactly what I wondered when I saw this

[@bensgarage9954]

It is necessary because the cooling system draws in raw water to cool the exhaust and the coolant in the closed system via a heat exchanger.

[@willytv275]

Great video - I just got a cobalt with the 8.1. Boat is mint, guy really took care of it but somehow he lost the hand pump for winterization. Is that just basically a bicycle tire pump? Does it have a schrader valve? If not, what is merc OEM number?

[@MarkSchuster-ym3iy]

Are the engines counter rotation? Oh you said it

[@MarkSchuster-ym3iy]

I hate the upside down oil filter. I’m looking at a remote kit

[@samhotstick13.28]

Great video,very informative,I have twin 496hos should be the same procedure.

[@childo74]

What type of pump do you have on your winterization kit 74-35001?

[@stevebrummer6570]

Thank you for developing this video. I've been searching awhile for videos showing how to winterize a 496 mag engine with closed cooling and haven't been very successful. I did have a question about whether you would recommend the use of fogging oil especially if the boat were to be kept on a boat lift on the water.

[@PerfprotechMarineProducts]

yes we definitely recommend fogging the engine when keeping the boat on a lift. In reality we normally do fog the engine anytime we winterize however the owner of the boat we winterized in this video did not want the engine fogged for some reason.

[@childo74]

@@PerfprotechMarineProducts Mercruiser recommends that Fuel Injected engines are not fogged because it stops up the injectors very easily.

[@robertreese2600]

Fantastic video. Thank you.

[@jhill1023]

Quick question, After you run the antifreeze through the engine, are you supposed to flush the antifreeze out or leave the antifreeze in the system over the winter? Ive seen in other videos that say to flush the engine out and leave it dry over the winter.

[@PerfprotechMarineProducts]

+Jeffrey Hill Leave it in to prevent corrosion over the winter.

[@Mappy-xn1om]

that was awesome !

[@eliritz7868]

awesome video