454 Mag MPI getting hot


L

Lafuerza

New member
I took risers off and risers and manifolds looked like new. Cleaned it up put back together with new gaskets. Replaced sea water impeller and housing which looked fine. Replaced spark plugs with oem and gapped to .035 per motor spec. Also took thermostat housing off and replaced thermostat which was bad and rusted.

Turned motor on and j initially idled fine and kept temp steady in middle at 180. Riser amd manifolds temps rose to 140 on starboard to 120 on port riser and about 10ndegrees less per side for manifolds.

In 3rd run noticed temp needs started climbing quickly. Shut it down. Risers were 170 degreed or so.

any places too look. I have a suspicion some gunk got loose and made it's way into cooling system. Thoughts appreciated
 
Kinked intake hose on transom assembly, oil coolers plugged under engine. disconnect intake to sea water pump and ensure you have a full hose full of water.
 
This boat is new to me and is a restoration. Motor ran well with justvrisers getting hot. I had to clean out a lot of gunk. I'll pull the hoses off the coolers and see what's going on.
 
You may have bravoits going on.
After flushing and see its all clear, remove the hose connection at the transom behind motor. See if it looks like this

Bravo clogging.jpg
 
Pulled hoses apart in sections and flushed. Couldn't get to those lower hoses but got a good flush in both directions.

Ran motor and risers/manifolds stayed under 100 degrees. Engine stayed about 160 except when going from 1500rpm to idle. Then it bumped up before coming back down.
 
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