Running on fumes

FlyingV5

I wonder how far my Hurricane boat can go with the fuel gauge on empty? Took some friends to dinner last night. 1st on-the-water cafe we stopped at told us 1 1/2 hr wait for table, but they had lots of empty tables!? Plus, the gas dock was closed at 7:00pm, still broad daylight on a Saturday. So we ran on down the lake a few more miles to what turned out to be a wonderful new place where we had never eaten, then headed home in the dark. Gas gauge was initially jumping between 1/4 and E, but soon it quit jumping. I got up on plane and throttled back to 4000rpm, figured I would get as close to home as I could before it quit. For a half hour we cruised along on Empty, and pulled into the slip still under power. Hooray for whoever calibrated the fuel gauge, I'll never do that again!

Ernest_T

I think it has to do with how the sending unit is designed.  The ones I've looked have the bottom sensor a few inches above the bottom of the tank, so when the fuel level hits the bottom sensor, you still have a few inches of fuel in the tank.

One thing that I've noticed on my boat is that the fuel gauge drops more rapidly the closer it gets to empty.  I think this is due to the shape of the fuel tank.  On my boat, when I hit 1/4 of a tank, you can almost watch the needle move for that last bit of fuel.  When I get close to 1/4 tank, I'd better be within sight of a fuel pump.

nquirk

Unfortunately I've never seen these analog fuel gauges be really reliable.  However, another option (but not inexpensive) is if you have a newer engine, many manufacturers have a monitoring system (I have a Mercury with the Smart Monitor system)  Once calibrated upon installation, it then monitors fuel flow.  Having been told the capacity of my fuel tank, when it hits a low range, it'll flash and tell me along with the number of gallons consumed and my current flow/consumption rate to give me an estimate of range remaining.

FlyingV5

OK, here is the math. Fuel capacity of a FD196OB is listed as 29 gallons. I poured in two 2 1/2 gal. lawn mower cans, so say 4 to 5 gallons added. Then we ran about twenty minutes to the fuel dock and took on 26 1/2 gal. So there is around two gallons left to account for +/- and we burned some of that. It was empty.

So the gauge is actually very well set up in that it shows a reassuring 1/2 tank+ for a long time, then gives a useful reserve after a rapid drop to E.

nquirk

@FlyingV5, that good news.  You're very fortunate and the most important part is not how it works, but that you have confidence in it because you know what 1/2 and E really means.