Single Point Drain - To Vent or Not to Vent?

[mikedj]

I have a 5.0L MPI with a Single Point Drain system. The owner's manual has slightly different procedures for Boat in the Water and Boat Out of the Water draining. In the Boat in the Water section, it says to open the single point knob and then remove the thermostat housing vent plug within 30 seconds. In the Boat Out of the Water, there is no mention of removing the vent plug. Why the difference? Could it be a misprint?

Thanks,
Mike

 

[Great lakes pirate]

I pull the vent when draining on land. It makes the process go alot faster.

 

[Lazy Daze]

I've never really thought about it before - like Pirate, I always remove the plug regardless. But, I suppose that when out of the water, it'll vent through the water intake on the drive.

 

[mikedj]

But, I suppose that when out of the water, it'll vent through the water intake on the drive.

This may be the key. I checked the book and the the air-actuated single point, manual single point and manual 3-point systems all say the same thing - in-water pull the vent, out-of-water, no mention.

I couldn't figure out a reason why it would hurt to pull it, but I wanted some more opinions, just to make sure.

Thanks for the feedback,
Mike

 

[mikedj]

I finished this today and it worked as you all suggested. I started with the single point valve (as per the manual), then opened the vent. Definitely flows faster with the vent open. Worked great.

Thanks again,
Mike

 

[Lazy Daze]

Good to hear - glad it worked out!