View Full Version : How to tell when my gas tank is full?

08-13-2011, 10:23 PM
I have a 2005 Outback DD. The gas gauge is not very consistant with how much I have in the tank. It appears I have a 28 gallon tank. When I fill up, its hard to tell when im near full and Ive overfilled a couple times. Just kinda frustrating....... When I go out for a long day I want to make sure the tank is full. Any others with this problem? Any advice?

Ive read also people just saying to fill up and go by 5 gph, but sometimes I use more than that... First trip I calculated 8 gph, but since then Ive been more easy on the thottle and its closer to 5-6.

Help please!

08-14-2011, 01:22 AM
Can't help you with calculating how much you'll burn per hour as that totally depends how hard you're running, what you're doing, etc.

However when filling, I listen to it. My gauge is off a little and I know I never burn down as close to empty as it says I am. So when filling I listen to it and when the pitch changes a little I back it off right away or completely stop. You can hear it start to backup up the fill/vent tubes. Kind of like if you turn a garden hose on that's empty and listen for the sound of the water as it is getting closer to coming out the end - that's about the only thing I can think of to compare it to. I usually don't lock the gas nozzle on either because by the time it kicks itself off it's way too late.

08-14-2011, 03:34 PM
Berg is spot on. I never lock the handle and I put my ear to the fill cap and listen for when it starts to get full. Then I slow down so I can get as much fuel in as I can. If it starts to slosh, an air pocket can get hung in there and the tank won't get completely full. I think I average about 4 to 5 gph and I ski, surf, and wakeboard with anywhee from no ballast to about 1500 pounds for surfing. 8 gph is a lot for an outback.

08-14-2011, 05:17 PM
Same hear, listen to it is about the best way I know, still splash a little sometimes

08-15-2011, 10:29 AM
by Listening, I place papers towels under the cap just in case and use more to close up the hole some more, it seems to help me hearing the sound change in the hose.

New Guy
08-15-2011, 11:29 AM
Since we are on the topic of fuel. How much is left once you get to E?? I always wondered but I am too chicken sh*t to run out.

Also what fuel are you guys running 87 or 93?

08-15-2011, 11:53 AM
I did it again this weekend! Realized tank was full when I heard that liquid gold splashing into the lake! DUMB, DUMB, DUMB.

I've been running 87 & always treat with Marine Stabil.

08-15-2011, 12:25 PM
Since we are on the topic of fuel. How much is left once you get to E?? I always wondered but I am too chicken sh*t to run out.

Also what fuel are you guys running 87 or 93?

Friend of mine had to drain tank for repair. He ran boat to E and then still drained 8 gallons out of tank in his Outback.

08-15-2011, 12:30 PM
I'm too chickenshit as well. On mine I've seen mixed reports of either a 30gal or 40gal capacity. Most I've ever put in is ~28gal andI'm sure there was more left in there - just not sure how much! I'm thinking $100 per fillup is painful enough. Pushing to 40 gal at $3.85/gal doesn't sound like much fun to me.

I run 89 typically and occasionally run 92 octane but my engine was rebuilt with a hotter cam and valve train. Read on the Indmar site that you're not gaining anything running higher than 89 octane. Same on other Auto Forum octane topics unless you are having pinging or detonation problems or your PCM is tuned/designed for the higher octanes.

New Guy
08-15-2011, 03:16 PM
I'm typically the same Berg but it would be nice to know how much is left for that time when you are really in a bind.

08-15-2011, 04:24 PM
I check the engine hours since the last fill up and times that by 5. When I am a few gallons from that number, I set the pump on the lowest setting. It will USUALLY click off by itself without spilling a drop but not always. Another method is to listen to it and when you hear it gurgle, that means it's about to overflow. But most gas stations are next to a busy road and I can't always hear the gurgle too well.

I run 89 octane per the owner's manual.

08-15-2011, 10:55 PM
I just use the hours as a check as well. I don't trust the gauge. My buddy just bought a 2003 Super Air, and it has a really neat feature. It's computer monitors fuel flow and tank level and has a display that tells you "hour to empty" like the newer cars do. It is an approximation based on averages, but I bet it is fairly accurate. Kind of nice.