2001 4.3 2BBL Sudden drop in temp

[THenning]

I have a 2001 sea ray 182 BR.

4.3 L with the 2 Barrel Mercarb

Had the boat out for 8 hours on the chain. Temp stayed about 170 Deg all day long until the last 10 min.

Temp suddenly dropped to 130 Degrees and stayed pegged there in the last channel.

Any ideas what to look at first? Sea Impeller in lower unit? Impeller on front of engine? T-Stat? Sending Unit? I did hit some mud, but that was ~1 hour beforehand.

Thanks

 

[nola mike]

Sounds like an issue with your gauge/wiring/sender. A stuck open tstat probably wouldn't cause it to drop that quickly, especially if the engine was already warm

 

[Grub54891]

Some debris got stuck in the thermostat.