Fogging Crusader MPI

Will Fish

Petty Officer 2nd Class
Joined
Jul 8, 2011
Messages
164
new used boat to me with twin Crusader 5.7 Captain Choice MPI's. I've always had merc I/Os w/ carbs so this is all new to me. In researching winterizing these motors, Crusader says to remove the plugs, "use an aerosol-type fogging solution and spray a sufficient amount of oil into each cylinder", then turn crank by hand, and reinstall plugs.

1. is there a preferred fogging spray?
2. how much is "a sufficient amount? I know excess oil in each cylinder can hydro lock the motor.
3. will this process harm the motor, i.e. sensors, platinum spark plugs
 

tpenfield

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Jul 18, 2011
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17,620
The Mercruiser method for fogging and MPI engine is to mix 10% 2-cycle oil with a short supply of gas and run the engine(s) on that for about 10 mins or so. Not sure why Crusader would prescribe a seemingly harder method . . . but . .

Any quality fogging spray should be fine
I'd do about 3 second blast
Since you are going directly into the cylinders, it should not effect any of the sensors. If you sprayed into the throttle body, then it would get to the sensors.

I would spin the engine with the starter briefly while the plugs are removed just to avoid any hydro-locking possibilities . . . plus it will move the fogging oil around a bit and get the valves.
 

harleyman1975

Ensign
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May 12, 2003
Messages
959
Never fogged a motor in my life. If just seasonal lay up it will be fine in my opinion. I long term lay up then that is a different story.
 

Bondo

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Apr 17, 2002
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Never fogged a motor in my life. If just seasonal lay up it will be fine in my opinion. I long term lay up then that is a different story.

Ayuh,..... Ditto,.... 5 or 10 Years maybe,... 6 months, not worth the effort,...
 
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