Fuel tank access

[Paulus]

My 40 Gal diesel tank sits under the cockpit sole with about 1" to spare between the top of the tank and the sole. There's a sending unit mounted on top, (note the yellow wire going up to the sender in this pic - the sender sits right under the small darker reinforcement pad under the sole)
The black line coming from the top center is the tank suction; the grey-ish line is the return - there is no bottom penetration - no other holes except for the fill and vent, on the other (top) side.



but I have no fuel gauge. Instead, the PO would get fuel based on engine useage - using 1 galon per hour as his measure. I have done the same thus far, and it works (quite accurately, I might add) but in a weak moment, I bought a fuel gauge





and attempted to connect it. The Gauge reads from 30 Ohm to 260 Ohm (I believe)

Long story short, I have concluded that the sender has failed (stuck on 35 Ohm, which is the reading for empty) - each time I attempt to get a reading I get "Empty", even though I know the tank is about full.

My question: I am planning on cutting an access hole above the sending unit in the cockpit sole and install one of those 6" inspection access plates... This will give me access to the sender (and fix/replace it), but also, with the sender removed, access to the tank itself for suctioning water off the bottem (currently not possible) and even access for a tank cleaning (never done to my knowledge, since it was installed new in 1992).

I am confident I can install the inspection cap flush (sunk in the 3/4" plywood) with the cockpit sole and close it up nice and tight.

Should I leave well enough alone and continue reading the engine hour meter (the tank has not given any "real" indication that it need cleaning - black goobers are easily taken care of by the Racor 500 series filter/water separator....

Thanks in advance for any and all input.

[Quetzalsailor]

You can certainly install a Beckson access plate adequately.

You might also consider one of those tape-on-the-side type indicators. A little pricey but, hey! You can buy one of those things with a switch to indicate fluid levels sequentially in up to four(?) tanks. In our case, fuel, sewage, and water. Besides price, our water tank is quite irregular in shape so relative depth is not directly indicative of contents.

[Shoalcove]

Personally, I wouldn't cut a hole in my cockpit sole just to put in a fuel guage. If I did I would want something tougher than a plastic fitting. Tim is using some nice SS ones on his Fisher rebuild; perhaps he'll provide us with the source. I'm sure they would work fine but I'd stick with your previous method or go with Quetzalsailor's idea rather than risk the leaks.

[Paulus]

Never thought about the stainless steel access plate option... Tim, can you refer me to a site where they sell these?