Thermostat(s)

[61SkiBee]

I've been running my Ford V8 inboard "Interceptor" marine conversion in my Trojan SkiBee runabout without a thermostat for years. I don't like to have the engine running so cold, but I'm concerned about any possible overheating damaging the water cooled exhaust manifolds. There appear to be two thermostat housings, one with a wire that goes to the temp gauge. I don't know if the sending unit is even working, but the gauge stays on "cold" all the time.

Anyone have experience with how the water circuits work on these marine conversions, and what thermostat or thermostats should be used? Do the exhaust manifolds get cold water regardless of how the thermostat is set up?

[NYRaider]

Thermostats are used to restrict the flow of coolant until the coolant reaches the desired temperature. When its reaches that temp the automatic spring opens allowing the circulation. There are many different types of temp setting thermostats... look at the bottom of one, the opening activation temp should be stamped into the lower housing. I have seen ones as low as 75.

As for the wire...run the engine for a while and then feel the manifold around the thermostat housing, the temp there should be the same as the rest of the engine ( check several places as a comparison)...if it's colder, then you have a carbon buildup blocking the exhaust post below the housing.

As a side note...I hate thermostats! I make it a point to remove them from all my cars and boats. I would rather use a piece of cardboard over the radiator to warm an engine that rely on a spring that gives out at the most inconvenient time.

[61SkiBee]

Thermostats can be a pain, but an engine running too cold is not good for efficiency, and it can reduce engine life too. This is especially true for "open" coolling systems like most boats have. All they get is cold water straight from the lake, and the engine runs stone cold, never getting a chance to purge contaminants from the oil. Hot oil burns out damaging acids

I'm going to try to get some kind of thermostat set up this season. Wish me luck on not burning anything up!

If you're running a 2-cycle, of course, this isn't a problem. As I recall, your runabout is an outboard. No worries! Sometimes I miss outboards. But man, nothing sounds like a V8!