Trojan Boat Forum

I also posted this question on the Runabout Owners Group Forum, but anyone running a vintage inboard would perhaps have the answer:

I've been running my Ford V8 (292 ci "Y" block) 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?

if it is raw water cooled the exhaust should have a secondary hose that by pass the thermostat and goes directly into the cooling side of them
most of the older engine were made to run with a 160-165 deg. thermostat, the sending unit may be working but the water circulating is moving thru unrestricted so your engine is not able to build up heat
if you are up north anywhere north of I-10 in this case the water is colder most the year anyway, the engine needs to build little heat up to run at its best
hope this helps
todd
31 trojan Mio Mio

Thanks for the info! I think there may be a built-in bypass for wather to the exhaust manifolds. There is only one "pickup" hose going to the lake water. It's a bit of a complicated system.

I agree, the engine up to real operating temperature using only lake water, and it may never even get warm enough to make the temp gauge budge. This is not optimal for engine efficiency or logevity. Never gets warm enough to purge contaminants from the oil.

I might just hunt around for one thermostat and put it in the housing that has the temp gauge wire on it.

Thanks, too, for the info on typical thermostat ratings. I wouldn't want to run anything too hot.