1974 Mercruiser 225 Inboard Both engines recently rebuilt.Right one runs OK. Left one is overheating and when I pulled the plugs the electrode and tip were nearly burned off.I just bought the boat.I was told it was basically a 302 Ford motor. Does anyone know the firing order for a counter-rotating engine?Also any suggestions on what to check next. Wrong cam? Cam timing Off?

 

What about checking for cooling water flow first? You could have a plugged strainer, shut off sea chest valve, or a bad water pump, or just a belt off the water pump. Look at the cooling water overboard and make sure the flow is there. Feel the water lines with your hand. Are they a lot warmer than the other engine? Do all that first before digging deeper into the timing issues.

 

Is the impeller good on the intake water pump? You sure they cleaned the heat exchange out good on it. like jughead said look at the cooling water for the engine first "on boats all the time"


ED

 

Does it have a "counter rotating" water pump also? If you had the water pump changed, that could be the problem.