There is no air bleed. Did your previous Raw Water Pump (RWP) impeller disintegrate due to the corrosion inside the housing? Was this the first start of the season? Also, you said “
replaced the impeller and pump”. The rubber impeller is in the RWP on the crankshaft. Did you also replace the ‘circulation pump’ located on the block? Trying to figure out the history that led up to the overheating and make sure talking the same thing.
If you removed the RWP it’s easy to get the hoses backward, are you sure they installed correctly?
Also, if you wire brushed the RWP housing where the impeller goes it may not be sealing now or rapidly eroding the new impeller.
And was it running on a garden hose or in the water. If on a hose while on the trailer, did you get the expected water flow coming out of the exhaust, etc.?
Assuming no engine issues like an extreme lean condition, overheating is due to insufficient water flow due to not being pumped (like the busted impeller) or a blockage preventing the flow (like impeller debris in the system) or a broken connection and thus sucking air.
Please provide the history that led to the overheating as well as pictures of the old impeller core and the inside of the RWP housing and the good folks here will help you get to the solution.
