Re: MerCruiser Alpha 1 running hot
Update. I finally had a chance to get the boat out on the lake today. Before doing so I cleaned up the poppet ball valve assembly.After coming down off of plane with the gauge on the dash reading close to 170 degrees I put the IR gun right on the brand new sending unit and it read from 136-145 degrees while running about 1300 rpm. The 170 reading on the dash gauge hardly moved if at all.
The elbows had a reading of about 125-135 degrees with the post side a tad higher. The exhaust manifolds had a reading of 185-200 degrees.
When I installed the new thermostat I cleaned both mating surfaces good and used a new gasket with the 4 copper rivets in it that serve as a ground. Before I replace the gauge on the dash as it's 19 yrs. old I might try adding a ground wire right to the sending unit and see if that makes a difference.
