With the price of gas, maybe I shouldn't complain, but I before I went to the gas station, the VDO fuel gauge on my 87 Formula 242 454/330hp showed the needle in the red "reserve" area. I put exactly $100 bucks in - about 27 gallons. (would have put more in, but the pump was incredibly slow) since I am on an inland lake with limited speed zones and mostly no-wake I figured I'd be fine.

We get the boat in the water, gauge shows about 3/4 full. Boat (per specs) has a 104 gal. tank!

Ran boat a couple of hours...only a few higher-speed runs (my friend was getting white knuckles at 40mph LOL)

Fuel gauge has barely moved.

Any thoughts? Will it suddenly jump into "reserve" when it gets closer to low?

Sure -- it would be great to have a "magic" fuel tank but I know better. And I don't want to run out unexpectedly. Anyone ever have a similar experience with an older Formula?

Do you drain the tank over the "off" season? I have to tear into a 1989 Checkmate tank to clean her out, and once that's done, I will be draining yearly. The sludge developed from the ethanol and additives has probably hung up your guage gear, but who knows? Maybe you found the magic we all need..

Did you check the fuel level (via the gauge) after you had the boat back on the trailer? Sometimes the boat attitude is different on the trailer than on the water. This different attitude may give you two different readings. Don't know if this helps but it's a cheap way to start your trouble shooting.

Sounds like to me that 87 fuel sender is about to go south. I bet if you take it out and move it up and down it will do just what you said and go from 3/4 to reserve with no stop in the middle. Find a new sender that works with VDO and make sure to set it up per instructions to get a good reading.

It is likely that the tank fits your hull between the inner most stringers - at least most do. Think about it, it is likely a V shape on the bottom half of the tank, and it is rectangular on the top half of the tank. Yet the sender merely floats from top to bottom.

So you're right - likely the gauge is going to move from 1/2 to empty way faster than it moves off full or 3/4. Plus your sender is at the back of the tank, so the natural lay of the boat in water at rest will have the gauge read higher.

My bet is your fuel gauge is fine. Fill it up - I bet it sits on full for a long time. And it will drop from 1/2 to empty in no time. That is pretty common.

You should be able to get to the sending unit from the engine compartment, start doing some trial and error with some of the above ideas, or fill it up and run it a few times, remember that boat sat for sale for a while, and from the way it sounds it wasnt being used while it was there

In the engine compartment you can see the wires and hoses that go to the tank check the ground wire some times it will get loose.

Yup, totally agree with you Mentalpause.
(great name by the way!! I suffer from the same condition frequently. )

My wife gave me that name to put on the boat a few boats ago. Seems to have stuck.

Thanks for the help, guys. Mentalpause's explanation may be likely - though it is also the most hassle-free. If I don't see any more movement (very) soon, I will investigate further using the other suggestions.