F25 engine trouble

[kjpf25]

Put a new themostat in the '79 Chrysler 318 and while the engine runs cool now, never over 180, after approximately 40-45 minutes of running, the engine starts running rough then dies. I can get it started again but have to keep the throttle really high. Any ideas?

[Commissionpoint]

Hot coil syndrome perhaps?

[larryeddington]

raw water cooled t stat is 140 to 142 deg. Fresh water cool is up to 180.

[kjpf25]

Larry, it uses lake water. Is that "raw" or "fresh"?

[kjpf25]

Larry, please ignore the previous question. Did a little research and now just need to see if the boat has a heat exchanger or not. Where would it be located?
Thanks,
Kevin

[Big D]

When you replaced the t-stat was there water there or coolant? Coolant = fresh water cooled.

[Big D]

If you can keep it running at higher rpm after, it may be fuel related.

[kjpf25]

I talked to the mechanic that replaced it and he says it is raw water cooled he put in 160 degree thermostat.

[larryeddington]

according to what I understand raw water t stat is 140 to 142 in the 318s. The reason is that at higher temps, such as 180, Salt water is much harder on a raw water cooled engine. IMO 160 will be okay for freshwater use. But others may have a different opinion I put 142s in mine as originally installed.