Re: merc 3.0 installing engine temp sender
If its a 1 wire sender, Nope.
1 wire engine senders use the threading as a ground, it's the electical resistance with the ground and the sensor that tells the gauge where to point.
Try not to over tighten you'll break the threads on the sender.
Sender threads have a slight taper and do a good job at sealing on their own. I use a 3/8" rachet with a 3/4" or 7/8" Deep socket, you can use a Boxed end wrench but will have more torque at hand than a med rachet.
