Re: 1988 88 spl temp gauge?
It's a good idea to have a temperature gauge because it gives you a way of monitoring the effectiveness of the cooling system, rather than depending on the warning horn, which often comes too late or at an inconvenient time.
Each gauge requires its own special variable resistor sender and wire. The sender would be mounted on the cylinder head using one of the cylinder head bolts and a Z bar. Be sure to order the kit rather than just the gauge. If you want to monitor both banks of cylinders, you would need either two kits, or two senders and a switch.
http://www.downloadingfiles.co.uk/teleflexfiles/gauges/Outboards.pdf