running without a t-stat

[sailor58]

quote opposedtwin:

Well…maybe I pulled it too soon. I tested the little bugger in some hot water on the stove and it appears to open and close. Still, if I couldn’t keep my hand on the housing, isn’t that too hot? Does anyone happen to know at what temp these things are designed to open? To repeat, it’s a 1959 lark.

I had the thermostat stick on my 350 Chevy boat motor on my second voyage this season. Scared the crap outta me! Just getting up on plane, the high temp alarm goes off, and what looks like smoke is coming up through the deck hatches! At first I thought I was on fire! Opened the hatch and there was a 3′ jet of steam coming out of the blow-off tube on the heat exchanger. I had my own personal fog bank of vaporized coolant around me. I threw the anchor, waited for the engine to cool enough to refill the cooling system with water, got it running again, the thermostat started working, and I motored home. Changed the ‘stat the next day.
Shared the story so that I could say," I won’t ever trust a thermostat once it has stuck."
best,
Larry

[opposedtwin]

well, I re-installed the t-stat after seeing it function properly on the stove top. today I tested it in a barrel and on the water. it pumped in a most beautiful way the whole day! i’m guessing jeff was right. it sat for a couple years and was probably stuck a bit. here are some pics of the water pumping and of the innards.

one less thing I have to worry about! 😀

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[outbdnut2]

Glad you got it cooling – I’ve also got a ’59 35 lark. If it sticks again, get Sierra #18-3553, or 18-3672 gets you a gasket with it. #18-3674 is a complete kit with gaskets and spring.
Dave

[jerry-ahrens]

Thermostats on outboards [and stern drive engines for that matter] are one of the most neglected parts of the cooling system. I’ve seen more ”stuck open” T stats, vs. ”stuck closed” but either can happen. This summer I bought a 1988 Merc 25 tiller. After the usual carb work and a new impeller, it ran pretty good. Still, it always seemed a little lean at idle speed. Turns out, someone had removed the thermostat, and was running it without one! After a new T stat and grommet, it made a remarkable improvement in idle quality, and overall running. That engine could never really warm up, because of to much water flow. Thermostats should really be checked or replaced, when servicing the impeller.

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