Primer bulb to transfer gas into another tank.

[joeboater7]

Hi,
The other day I was towing my boat and was dangerously low on gas in my vehicle. I decided to disconnect the gas line going into my '90 115 hp mercury and remove the adapter at the end of the line, and thought I would smartly squeeze the primer bulb while dangling the open end of the fuel line into a gas can. But to my surprise I got a few small squirts of gas and then no matter how much I pumped the bulb, nothing but air moving back and forth. I had the fuel line draped over the edge of the boat and the bulb facing down, so maybe that was the problem? Or does the bulb work in conjunction with some other valve in the motor to create suction? When I reconnected the motor adapter and tried pumping into the spare gas can, I also got nothing. I then plugged the line back into the motor and still pumping the bulb did nothing. Then I lowered the motor from towing to operating level and pumped the bulb, and then it did pull gas and the bulb got somewhat hard. What gives? I would like to know for future use how I can use the bulb to remove gas from the main tank. This would be handy for end of year and also in a pinch if I needed gas on the road or around the yard.

 

[racerone]

The primer bulb is nothing but a manual pump.-----Moves fuel in the direction of the arrow on the bulb.-----Should work doing what you did.

 

[joeboater7]

I thought so too! maybe bulb is bad. But why does it work fine when connected to the motor?

 

[racerone]

I can't tell from here.----It should work with a good quality bulb.

 

[GA_Boater]

I do this all the time. I have a spare connector like the hose would plug into on the motor to open the hose. Works fine to siphon gas from one tank to another.

What is on the end of the hose when the adapter is removed? An open hose or a spring loaded shut-off?

 

[joeboater7]

I can't tell from here.----It should work with a good quality bulb.

hm, might have to replace bulb. maybe it only works when connected to the motor because the motor has it's own 1 way valve?

 

[joeboater7]

I do this all the time. I have a spare connector like the hose would plug into on the motor to open the hose. Works fine to siphon gas from one tank to another.

What is on the end of the hose when the adapter is removed? An open hose or a spring loaded shut-off?

Once I removed the adapter it was just an open hose, nothing else on the end. I would assume it was a bad bulb, except it did work when connected to the motor. I might try it again holding the bulb upright.. maybe having the arrow pointing toward the ground messes with the suction?

 

[Faztbullet]

If tank/fuel line has a anti siphon valve it will do this...

 

[roscoe]

I'v done this several times.

If the gas has to go thru a fuel water separating filter, it will not work.

Also, helps to have the primer bulb vertical -- ARROW UP. Seems to help the check valve work better. But it will be slooooow.

I've had better luck taking my spare fuel line, no fittings, just the primer bulb, and lowering it into the fuel fill, then just pump it out with the primer bulb.
I pumped out about 18 gallons from a buddies boat, in about 20 minutes just last week.
I have an small electric transfer pump, but it wouldn't fit in his fuel fill opening.

 

[Texasmark]

I don't know if you can siphon with a check valve since there is a pressure drop across them and atmospheric pressure is like 1/2#/FT of elevation....not much. Something has to push against the spring to get the valve to open and that's the weight of the fuel in the line.

My thought was that you had the right idea, but after you got fuel flowing out the end of the bulb, jerk the bulb off and just let the fuel run out of the fuel line....with the outlet below the level of the suction tube in the tank...the more the merrier per the above comment.

 

[dingbat]

If your talking about a permanent mount, below deck tank, your trying to pull fuel against an “anti-siphon” valve….

Can’t “siphon” from the tank by design…

 

[joeboater7]

I'v done this several times.

If the gas has to go thru a fuel water separating filter, it will not work.

Also, helps to have the primer bulb vertical -- ARROW UP. Seems to help the check valve work better. But it will be slooooow.

I've had better luck taking my spare fuel line, no fittings, just the primer bulb, and lowering it into the fuel fill, then just pump it out with the primer bulb.
I pumped out about 18 gallons from a buddies boat, in about 20 minutes just last week.
I have an small electric transfer pump, but it wouldn't fit in his fuel fill opening.

There IS a fuel/water separator, so maybe that is why it didn't work! hmm. But strange it works fine when connected to the motor. What does the motor do that makes it work? Does it have it's own one way valve? I tried to simulate this by holding my finger tight on the end of the line, but it didn't seem to help. maybe I need to buy a small plug in to put on the end of the line, if i want to to this someday?

 

[joeboater7]

I do this all the time. I have a spare connector like the hose would plug into on the motor to open the hose. Works fine to siphon gas from one tank to another.

What is on the end of the hose when the adapter is removed? An open hose or a spring loaded shut-off?

Anyone have a link to this type of adapter that I could buy online?

 

[Texasmark]

There IS a fuel/water separator, so maybe that is why it didn't work! hmm. But strange it works fine when connected to the motor. What does the motor do that makes it work? Does it have it's own one way valve? I tried to simulate this by holding my finger tight on the end of the line, but it didn't seem to help. maybe I need to buy a small plug in to put on the end of the line, if i want to to this someday?

The fuel pump in the motor "sucks on it" while the engine is running after your squeezing hand pressure filled up the line with gas.