Got to work on the boat last weekend for the first time since Wilma. Prior to Wilma I was in the process of fixing an overheating problem.
I had been running the boat at idle speed for 30 minutes with no problems, got onto plane, and within a half mile the port engine pegged the temp gauge and steam was pouring out of the engine compartment. Diagnosis was a partially clogged riser which melted the rubber elbow coupler and shutter. Engines are raw water cooled Merc 4.3L's with Alpha 1 drives.
So now I have replaced all manifolds, risers, and thermostats. Ran on the muffs and found the port engine to overheat gradually at idle. I'm thinking my next step is to check the impeller as it is pretty old, is there anything else I should check while I'm at it?
I had been running the boat at idle speed for 30 minutes with no problems, got onto plane, and within a half mile the port engine pegged the temp gauge and steam was pouring out of the engine compartment. Diagnosis was a partially clogged riser which melted the rubber elbow coupler and shutter. Engines are raw water cooled Merc 4.3L's with Alpha 1 drives.
So now I have replaced all manifolds, risers, and thermostats. Ran on the muffs and found the port engine to overheat gradually at idle. I'm thinking my next step is to check the impeller as it is pretty old, is there anything else I should check while I'm at it?