I have a 59 Sprite with a1275 cc engine. 3 of my gauges don't work - speedo, tach & gas gauge. I get the relationship betw the speedo & tach but why the gas gauge isn't working puzzles me.
The 1275 is not original to the 59 sprite. The speedo is cable driven off the transmission. In 59 the tach was mechanically driven by a cable from the generator. The 1275 has an alternator w/o the mechanical hookup for the tach. Most 1275 conversions use the electronic tach from later Sprites. As far as the gas gage goes, it is not uncommon for them to not work. It is an electrical troubleshooting problem. Find a sports car club in your area and join it. Their members have been through all this and can help you. Check out www.healeyclub.org and www.healey.org
Check the sending unit for the fuel tank. Mine was bad and I had to pull the tank and replace it as it sits on top of it. Could also be the wiring connection to the unit - unfortunately it is a blade tupe connection on the sending unit - so tank has to be pulled.....Not a very difficult job - got a newunit from Victoria British for about $40.