TOPIC: Water temp gauge for '66 40hp Lark?

Has anyone converted a hot engine light to a temp gauge? Or is there a better way to add a water temp gauge?

Often though of that myself and there are sensors on the market that can be used. Here's a link that might lead you in the right direction.

If you are just doing this to add a gauge to the dash then it sounds like a fun project.
If you are doing to head off possible engine damage keep in mind the sender for this will react much slower than an actual overheat and subsequent engine damage will. Also not a good indicator of water pump health.
A water pressure gauge is pretty much an instant read gauge but then again you would just happen to be looking at it at the time pressure dropped.
Always good to run a bit of extra oil for protection during engine overheat if for no other reason.
Adding an overboard indicator is also not a bad idea to let you know you have water pump flow prior to leaving the dock.

Good things to consider. Thanks!

Thanks Cal! I had to replace the lower unit that was slipping. Brother in law had one, but had to replace the long driveshaft. And a new(used) voltage regulator cured the generator output problem. However, on the last sea trial checking these things out, the generator bracket broke (there is supposed to be a stabilizing link at the bottom, I didnt know about) and it jamed against the flywheel causing the flywheel nut to come off, so now I need to replace the flywheel (brother in law), after I clean up the crank shaft threads... Also, I did find a tach that connects to the high side of the breaker points for the signal. And a matching speedo should deliver any day now. Winter project . . .

Thanks Cal! I had to replace the lower unit that was slipping. Brother in law had one, but had to replace the long driveshaft. And a new(used) voltage regulator cured the generator output problem. However, on the last sea trial checking these things out, the generator bracket broke (there is supposed to be a stabilizing link at the bottom, I didnt know about) and it jamed against the flywheel causing the flywheel nut to come off, so now I need to replace the flywheel (brother in law), after I clean up the crank shaft threads... Also, I did find a tach that connects to the high side of the breaker points for the signal. And a matching speedo should deliver any day now. Winter project . . .