Strange Temp Reading

G

Greg Schoenberg

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A mile from the dock, I kicked both Crusader 220 hp WOT to bring her up on plane and blow some carbon out. I generally do this a minute or two before dropping them down to cruise.

Suddenly, the starboard engine went from a normal reading to 240. We shut her down and inspected. No steam, no sign of overheating. Hoses felt the same as the other engine. I contacted my mechanic, who was scheduled to come out tomorrow to discuss a fuel injection install. He said it could be a thermostat or a bad sending unit in the guage. In another hour, I'll check the radiator.

Wierd thing is that the boat is equipped with an alarm, yet nothing went off.

Any preliminary advice before I see him tomorrow.

Oh...seperate subject. Should I be rinsing salt spray/stains off the windows after each use or can that wait until the spring detail?

-Greg
 
The alarms use a seperate sending unit (from the gages)for each engine. SO the fact that there was no alarm is good as long as that are wired and working properly. PS, the alarm should sound for high water temp or low oil preasure. To test the alarm, find the sender for water and ground it and this should sound the alarm if the key is on. the only problem is the engine will need to be running or the alarm will sound for low oil preasure(normal condition if engine is not running). Hope this helps.
 
Perhaps you ran over a plastic bag or something that got sucked against the intake. If so, you may find that the next time you run the boat its absolutely fine, unless the damn thing got LODGED in the intake. I used to find that shutting down the engine and running the other one in reverse for a few moments would break the suction (depending on what you had snagged) and then you could fire the troublesome engine up again without incident. There might be a deeper problem somewhere, but perhaps not...
 
I wonder if it's one of those plastic bypass valves stuck...you know those older Crusaders had those big round valve in the thermostat housing.
 
Thanks for the replies, guys.

I think you nailed it Ram. Mechanic came out, did a pressure test for the FWC and determined that it would hold 6 lbs of pressure with no visible leaks. He believes it's a sticky thermostat, causing the radiator to slowly lose water. We filled radiator and it worked fine for the 2 hour trip to Bainbridge. He is returning later this month to install new or rebuilt carbs, replace both thermostats, and oil change.

Whew!

I suspect the reason the alarm didn't go off is because it's tied to impeller failure. The sea water cools the exhaust. If that process fails, the alarm goes off.

-Greg
 
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