I rebuilt the fuel gauge sender on my 1980 28' single. It had a four bolt Rochester swing arm mounted on an inspection pipe. Screwed directly on top of the unit was a gas level dial with attached sender leading to the helm gauge. This dial was also available without any sender wire. It is actuated magnetically - no wires in the tank. This is not the typical five bolt flush mounted sender used on more recent boats. That is a piece of crap but it is easily replaced. You can get the dial "bud" from a Rochestor distributor. That is what goes out. The swing arm is high quality and should be OK. I got mine from boatfix.com but that was a few years ago. If you have the five bolt flush mount the swing arm is probably shot as well.

My boat has no visible fuel gauge but before I took possession of it, the mechanic that was repairing the old sensor cut the foor and put in a new access point directly over the tank, mine is centrally located between the motors and the rear hatch, directly under the fixed floor. Just thinking this may be an option for you. JAM

If you have the four bolt Rochester replacing the dial bud does not require unbolting the whole swing arm sender. There is no wired connection. It is held in on top of the sender with a flange ring and tiny screws. I had to mess around with mine because my dial didn't fit well. It was larger and plastic. The original was metal. If you need to get at it a 6" access hatch in the deck will work well.

I had to take out the swing arm because I wanted to hand pump old gas out and the sender unit is bolted to the access pipe. That was a chore. The darn bolts were frozen. If you don't need to get in the tank don't. The old Rochester is better and more expensive engineering than the new 5 bolt flush mounts. The reason the new style breaks is because the sender uses electric wires and a rheostat soaking in gasoline.

If you need the magnetic guage, go to your local propane dealer, same as on a propane forklift.(about $12) I looked everywhere before I realized it was the same as a propane fofklift.Might have a swingarm with float if somebody needs one.--Ed