496 ho mag over heat
02-14-2025 | 11:54 AM
#11
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Joined: Oct 2024
Posts: 96
Likes: 39
From: York Haven, PA
There are lots of posts on this over the years.
Antifreeze is only good in these motors for 7 years, tops. As soon as it starts to turn dark, it needs to be drained and replaced. When it's dark, it is silting up.
Definitely need to open and clean the heat exchanger, and replace the end rubber gasket caps as a maintenance item. The pic above indicates how they create blockages.
How old is the seawater pump impeller? Is it flowing even water out of both exhaust tips? Your SWP impeller could be shot. Your SWP could also have wear not allowing enough water pressure for cooling.
Once you have done all of the above, report back.
Antifreeze is only good in these motors for 7 years, tops. As soon as it starts to turn dark, it needs to be drained and replaced. When it's dark, it is silting up.
Definitely need to open and clean the heat exchanger, and replace the end rubber gasket caps as a maintenance item. The pic above indicates how they create blockages.
How old is the seawater pump impeller? Is it flowing even water out of both exhaust tips? Your SWP impeller could be shot. Your SWP could also have wear not allowing enough water pressure for cooling.
Once you have done all of the above, report back.
02-14-2025 | 12:09 PM
#12
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Joined: May 2001
Posts: 24,204
Likes: 1,592
From: Worldwide
Well aware, as this thread is six months old.
HOWEVER, in Post #7, there is a new post from a newer member, asking the same question. Hence my reply.
