Mercruiser 470 repower 1978

[surchin]

Got the boat back today and took her for a run at sunset after work and the new plumbing is working fine

Engine runs cold at 100 deg or so. Flush the system at the ramp after coming in and seems to be working fine. I've learned most of the commercial fisherman here run open coolant systems like this they run their boats all day in kelp and raw water keeps the engines much lower temps.

I did notice a small dribble of a leak between the head and the block. Slight drip of water down the outside of the motor I didn't see it before as it was behind the heat exchanger not sure if coolant would have leaked from there. When it would boil over out the cap it would not have been possible to see it.

Anyway. Glad to get the boat back with a quick and cheap fix. Maybe not how the motor was designed or the best technical fix but I ll see how it goes. Maybe someone else can benefit from my trials here.