1999 18.5 bowrider temp guage going crazy need help

[eddien22]

I have a 1999 18.5 bowrider with the 4.3L 190hp engine. I took it out today and it started great as usual and ran perfect as usual. Then after about 15 min of run time iwas in a no wake zone and noticed the engine was running really rough. I looked down and noticed that the temp guage was going back and forth like crazy. It ran very rough and finally died. I restarted it and same thing. I finally got it back to the dock to load up not solving whatever went wrong. It still runs rough at idle and dies after about 20 sec in idle. Temp guage also still goes haywire. If any one has any advice I would greatly appreciate it.

Thanks
Eddie

 

[ddevriese]

Thermostat

Could be the theromostat, Eesiest thing to do is to pull it out and see if problem goes away. They are cheap so you could also replace it. It could also be a loose wire on temp gauge but that woudl not cause rough idle