Runs out of fuel at 1/2 tank?

[malayan]

Runs out of fuel at 1/2 tank?

I have a 21 gal tank.... I fill it up till it clicks..

I run for about an hour 8 gal or so... then it acts like it runs outa gas.

I pump the ball while condition is acting...no change??

I figure the fuel line is collapsing or pump works but failing. Ruling out clogged vent today.
Now it shows empty at level on trailer. I will pump it out into cans and start from scatch.

I have a 1989 Force 85 HP Outboard.

Thanks for your help or ideas

 

[Chris1956]

Re: Runs out of fuel at 1/2 tank?

Is the fuel tank vent clear? Does the bulb collapse, or does it suck air? If it sucks air, the fuel pickup in the tank is too short or has a leak.

 

[Mark42]

Re: Runs out of fuel at 1/2 tank?

Is there dirt in the bottom that could be clogging the pickup tube?

 

[kandil]

Re: Runs out of fuel at 1/2 tank?

Now it shows empty at level on trailer.

it sound like you might have a leak in the tank.is the tank built in?

 

[Bob_VT]

Re: Runs out of fuel at 1/2 tank?

A.... your fuel gauge is wrong and you are out of fuel........

or

B..... there is a leak in the fuel pick up line about 1/2 down in the tank

 

[malayan]

Thanks guys...here is an UPDATE

Thanks guys...here is an UPDATE

Completed Today:

1. Vent good
2. checked fuel lines ...Good
3. Checked filter...very Clean ( Glass see thru style)
4. Checked Motor Filter Screen...very Clean

YES! Built In Tank Factory.. Aluminum. Hose goes to top then no access to down tube All welded from there... Downtube is built in to the tank .

Gauge reads empty at level so I am gonna pump out any remaining fuel (if any).
Start from there.

Thanks Guys and I will update today again...

 

[Bob_VT]

Re: Thanks guys...here is an UPDATE

Re: Thanks guys...here is an UPDATE

My only other thought is that someone tried to clean the tank and the pick up line is bent

 

[Gary H NC]

Re: Runs out of fuel at 1/2 tank?

Pull the fuel sender and see how much fuel is in there.
I would think if it were leaking that much fuel you would have a really strong smell..
Where the fuel line from the motor connects to the tank does it not have a brass screw in fitting?

 

[malayan]

Re: Runs out of fuel at 1/2 tank?

No Fuel leak as I would see it when draining the hull.. Good Guess though..

and YES! it does have a brass tube fitting for the hose to connect to the tank...then 90 degrees into the tank.
I took a wrench and it UNSCREWED......YES! .

Now I have the tube out and only 2 " of fuel remain... Gauge is Correct.

No problem with the tube. it had a rubber end with a screen wrapped around the end ( no debris what so ever ).

I am applying thread tape and (since it is off) installing a brass tee to run a reserve tank hookup.

Question though??

I measured the permanent aluminum tank and it was 6" deep X 22" wide. I don't know how long because I think it goes under the floor ( I measured at least 23" long till it goes under the floor. it is stamped 21 Gal . Seems a little small . They couldn't have miss marked it could they? I will stick a measure tape through the tube hole and see if i can get an acurate length.

How long should it be for a 21 gal tank. That ought to boggle a mind or two

be back soon

Thanks

 

[dade61782]

Re: Runs out of fuel at 1/2 tank?

1 cubic foot will hold 7 gallons

 

[ondarvr]

Re: Runs out of fuel at 1/2 tank?

Since its empty just fill it up and see what it holds.

 

[ondarvr]

Re: Runs out of fuel at 1/2 tank?

I had a 90hp Force, it sucked down more fuel than any other engine I've had. 8 hours on 21 gallons would be good for that motor, so it sounds like the gauge stuck.

 

[Bob_VT]

Re: Runs out of fuel at 1/2 tank?

I measured the permanent aluminum tank and it was 6" deep X 22" wide. I don't know how long because I think it goes under the floor ( I measured at least 23" long till it goes under the floor. it is stamped 21 Gal . Seems a little small . They couldn't have miss marked it could they? I will stick a measure tape through the tube hole and see if i can get an acurate length.

How long should it be for a 21 gal tank. That ought to boggle a mind or two

be back soon

Thanks

6" x 22" x 23" =3036 cubic inches divided by 231(cubic inches per gallon) = 13.14 gallons I would call it a 12 gallon tank when the pump clicks off leaving 10% for expansion.

Your 85 Force will probably burn upwards of 8.5 gal/hour at wide open throttle.

 

[malayan]

Solved...

Solved...

The tank legth measured 44" before the tape stopped.
So that is 6"" X 22" X 44"
Yes and when I fill , need to make sure it is level and fill SLOOOOW or the wave of the fuel will shut off the pump.

Question. I have a nice vent overflow going way up my transom to exit out the rear after looping high first.

I heard that you should not fill the tank full. What would you guys recommend for MAX gallons so it will not spew out or is that possible the way it is looped high before exiting.

Thanks again...

 

[malayan]

Solved!

Solved!

The fill tube had a rubber hose on the bottom end and someone pushed it too far up the fill tube.

Probably when the old owner put the screen on the end. it was too far off the bottom making it seem to run out of fuel at 1/4 - 1/2 on gauge.

The tank measured 6'' X 22" X 44" .......yep it is 21 gal.

Guess I got to fill Sloooow to get it full.
or
Does it supposed to click off at a certain percent leaving room for boat tilt?

I installed a tee in the fuel line for a reserve tank and a new Bulb with nice new rubber.

Testing it tomorrow... THANK YOU ALL!

 

[Mark42]

Re: Solved!

Re: Solved!

The fill tube had a rubber hose on the bottom end and someone pushed it too far up the fill tube.

Probably when the old owner put the screen on the end. it was too far off the bottom making it seem to run out of fuel at 1/4 - 1/2 on gauge.

The tank measured 6'' X 22" X 44" .......yep it is 21 gal.

Guess I got to fill Sloooow to get it full.
or
Does it supposed to click off at a certain percent leaving room for boat tilt?

I installed a tee in the fuel line for a reserve tank and a new Bulb with nice new rubber.

Testing it tomorrow... THANK YOU ALL!

Well, its good to hear it was just "short sticked"! I usually fill in a gas station on the trailer, so I can fill until gas shoots out the overflow. But usually it makes a whistle sound so I know its near full. Then I slow down the fill till it clicks off.

The high loop in the vent is to make it harder for water splashed into the vent from getting into the gas tank.

Where are you putting T for a reserve tank? Usually a 3 way valve is used for this purpose. The problem with just a T fitting is the motor can pull air from the tank and not gas from the portable tank.

 

[Chris1956]

Re: Runs out of fuel at 1/2 tank?

On those flat tanks, it is important that the fuel pickup be as aft as possible. I had an 18 Gal flat tank (6" deep) and with the fuel pickup in the front, it would run dry underway with 6 gal remaining. I moved the pickup to the rear of the tank, and I can now run it dry while underway.

 

[Silvertip]

Re: Runs out of fuel at 1/2 tank?

While you didn't explain where this "T" is or what the rest of that system looks like, I want to warn you that you may have just created a problem. You cannot feed a single line from two separate tanks unless you use a fuel transfer valve. Without it, when one tank is empty the engine will suck air from that tank. You also run the risk of overflowing one tank or the other siince both tanks cannot be placed exactly the same level. So via siphon action the higher tank can drain to the other. Make sure you think this through carefully.