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Engine Cooling Question

SoxFan

Jet Boat Addict
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Location
Wrentham MA
Boat Make
Yamaha
Year
2013
Boat Model
SS
Boat Length
21
Have had my 212SS for 3 seasons and love the easy winterization compared with my previous boats with stern drives.
Could be a dumb question, but with my 1.8 engines also being “fresh water cooled”, why does the jet engine not have drain plugs to release any trapped water?
Part of the old routine was to open the 4 drain plugs to release any water still in the engine to prevent freezing and possibly cracking the engine block.

I do rev each engine briefly on the trailer to get out what I can, then run it with marine antifreeze- just to be safe.
 

swatski

Jetboaters Fleet Admiral 1*
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Location
North Caldwell, NJ
Boat Make
Yamaha
Year
2016
Boat Model
AR
Boat Length
24
Have had my 212SS for 3 seasons and love the easy winterization compared with my previous boats with stern drives.
Could be a dumb question, but with my 1.8 engines also being “fresh water cooled”, why does the jet engine not have drain plugs to release any trapped water?
Part of the old routine was to open the 4 drain plugs to release any water still in the engine to prevent freezing and possibly cracking the engine block.

I do rev each engine briefly on the trailer to get out what I can, then run it with marine antifreeze- just to be safe.
I wouldn't get too crazy revving them up out of water, just a gentle blip.
The key is to raise the bow to let the water drain down into the pumps.

--
 
Last edited:

bumpy

Jetboaters Lieutenant
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Location
Ashburnham, MA 01430
Boat Make
Cobalt
Year
2020
Boat Model
Other
Boat Length
23
I used to have the same concern; I don't use anti freeze at all on the boat (used to in the fresh water shower tank, now I just drain) and haven't had any issues in 5 winters. The engines are supposed to be self draining, and I think they really are!
 

Gym

Jetboaters Admiral
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Falmouth, MA (Cape Cod)
Boat Make
Yamaha
Year
2006
Boat Model
SX
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23
What is not self draining are the water boxes. They retain a certain amount of water.
 
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