saltwaterchuck
Recruit
- Joined
- Aug 17, 2011
- Messages
- 1
I'M STUMPED. I just had my 302 Ford Marine engine professionally rebuilt and reinstalled in my '89 24' Bayliner Trophy with an OMC Cobra Outdrive . Once on step it overheated after a couple minutes of cooling properly. We cut power and it dropped back to within the 160 degree thermostat limits, but the temp spiked again every couple minutes whenever we brought it up on step. We pulled the thermostat and it ran completely cold -under 120. We then replaced the thermostat with a new one (another 160) and it did the same thing again. We then put in a new 140 degree t-stat and it did it again but seemingly less frequent. The engine would run at around 140 to 150 then every 3 or 4 minutes at around 3000 rpm or more the temp would quickly shoot up to over 200 and within a second or two drop back down to around 140.
Because the heat exchanger is new and the engine runs cold without any thermostat, we believe that the problem lies with the engine cooling system and not the raw water system. My mechanic replaced the outdrive impeller at the time of the engine R&R and he believe the flow is good on that side. I have a hard time believing that the all three t-stats were bad. The water pump is older but seemed fine. What seems odd is that it all operates correctly except for that periodic spike in the temp ever few minutes. HAS ANYONE EVER RAN INTO THIS CONDITION?
Thanks
Because the heat exchanger is new and the engine runs cold without any thermostat, we believe that the problem lies with the engine cooling system and not the raw water system. My mechanic replaced the outdrive impeller at the time of the engine R&R and he believe the flow is good on that side. I have a hard time believing that the all three t-stats were bad. The water pump is older but seemed fine. What seems odd is that it all operates correctly except for that periodic spike in the temp ever few minutes. HAS ANYONE EVER RAN INTO THIS CONDITION?
Thanks