Sieving gas from tank?

[sasto]

Re: Sieving gas from tank?

The pressure vs. vacuum got me thinking.....usually not a good thing. Could one block the vent, open the fuel supply line, and use something like a shop vac to apply pressure in the fill tube and force the fuel out the supply?

 

[Bluestream]

Re: Sieving gas from tank?

Ayuh,... I hate to inform you,... Your Wrong...

Per Coast Gaurd mandate, All gasoline tanks used in boats Must be equiped with a Anti-siphon valve...
Not a Check-valve,... There's a difference...
It's usually the hose barb at the exit fitting of the tank itself...
It requires 2lbs. of Vacuum to release fuel...

If your's hasn't been removed, it's stuck open...

Well I guess gravity siphon gives the 2lbs needed to draw fuel. I have done this on the last three boats I have owned and it works fine, Maybe the OP should just give it a try...

 

[paultjohnson]

Re: Sieving gas from tank?

If there was an anti-siphon valve at the tank, the feul pump would not be able to suck any fuel to the engine. I just used this method to drain my own tank and it works very well.

I tried this and I couldnt get any siphon action. I assumed it was an anti siphin valve. Im confused How does the fuel pump draw fuel, but trying to start a siphon by suction doesnt work, I got absoutly no draw from tank????????

 

[paultjohnson]

Re: Sieving gas from tank?

Ayuh,... I hate to inform you,... Your Wrong...

Per Coast Gaurd mandate, All gasoline tanks used in boats Must be equiped with a Anti-siphon valve...
Not a Check-valve,... There's a difference...
It's usually the hose barb at the exit fitting of the tank itself...
It requires 2lbs. of Vacuum to release fuel...

If your's hasn't been removed, it's stuck open...

That explains why I couldnt start a siphon with mouth suction... Need 2 lbs. Just curious, how many lbs of suction does a fuel pump draw ? Same as it puts out? 5-7 lbs or whatever?

 

[Beefer]

Re: Sieving gas from tank?

The pressure vs. vacuum got me thinking.....usually not a good thing. Could one block the vent, open the fuel supply line, and use something like a shop vac to apply pressure in the fill tube and force the fuel out the supply?

I think we've already gone down the road of why gasoline and shop-vacs don't mix....

 

[RotaryRacer]

Re: Sieving gas from tank?

Back to the original question.

I'd bet a pretty penny that that panel behind your ski locker is in fact the way that Larson intends for you to access that tank. On a Larson that I had earlier this year there was a similar panel and there were screws hidden in the matted down carpet. When the screws were removed it allowed one to pull the panel out and gain access to the tank.

Look around the perimeter of the panel and see if you can find some screws in the carpet. I'd be surprised if you don't find any.

 

[dsiekman]

Re: Sieving gas from tank?

Back to the original question.

I'd bet a pretty penny that that panel behind your ski locker is in fact the way that Larson intends for you to access that tank. On a Larson that I had earlier this year there was a similar panel and there were screws hidden in the matted down carpet. When the screws were removed it allowed one to pull the panel out and gain access to the tank.

Look around the perimeter of the panel and see if you can find some screws in the carpet. I'd be surprised if you don't find any.

Agreed. My old Cobalt had a similar set up. Once I pulled all of the crap out from under the bench seat I climbed in and took a closer look. There was a fairly large panel that allowed access to the tank and sender.

 

[paulspaddle]

Re: Sieving gas from tank?...solution!

Re: Sieving gas from tank?...solution!

Ah, the beauty of iboats....

(please excuse the so called 'yard' we're in the process of raising and sodding...not fun conditions to work in)

Step #1 was to disconnect the fuel at the water separator filter. I dropped the fuel line to the bottom of the bilge, but only what was in the line of those few inches came out.

Step #2 Ran a line up through the bilge drainage hole, attached to fuel line. Tried, but no sieve action.

Step #3 Put drain hose in can and carefully put a shop-vac "blower" end to the fuel tank. I didn't stuff it in there (just for the photo) for fear of blowing something apart.

Success! Worked great. Thanks for the suggestions.

[/IMG]



ps...yes I know those are diesel tanks, my neighbour was throwing a bunch away.

 

[hostage]

Re: Sieving gas from tank?

Is that a head in that picture? That looks like an odd place to have one.

-Hostage

 

[paulspaddle]

Re: Sieving gas from tank?

Back to the original question.

I'd bet a pretty penny that that panel behind your ski locker is in fact the way that Larson intends for you to access that tank. On a Larson that I had earlier this year there was a similar panel and there were screws hidden in the matted down carpet. When the screws were removed it allowed one to pull the panel out and gain access to the tank.

Look around the perimeter of the panel and see if you can find some screws in the carpet. I'd be surprised if you don't find any.

I couldn't agree more.

I can see the seem, I can even wedge a screwdriver between the panel and slightly wiggle it. I've literally gone inche by inche along that seem looking and tapping with a screw driver to find a screw or fastener of any kind.

I'm taking it to a Larson dealership shortly, see what they say.

 

[paulspaddle]

Re: Sieving gas from tank?

Is that a head in that picture? That looks like an odd place to have one.

-Hostage

Yup, its a head, yup its odd.

 

[jeeperman]

Re: Sieving gas from tank?...solution!

Re: Sieving gas from tank?...solution!

Ah, the beauty of iboats....

(please excuse the so called 'yard' we're in the process of raising and sodding...not fun conditions to work in)

Step #1 was to disconnect the fuel at the water separator filter. I dropped the fuel line to the bottom of the bilge, but only what was in the line of those few inches came out.

Step #2 Ran a line up through the bilge drainage hole, attached to fuel line. Tried, but no sieve action.

Step #3 Put drain hose in can and carefully put a shop-vac "blower" end to the fuel tank. I didn't stuff it in there (just for the photo) for fear of blowing something apart.

Success! Worked great. Thanks for the suggestions.

[/IMG]



ps...yes I know those are diesel tanks, my neighbour was throwing a bunch away.

Being in Manitoba, I hope you lower that lower unit soon and have all the water drained from the engine too.

Maybe that floor panel has those plastic "christmas tree" type retainers?
Like what holds the insulation to the underside of your car hood.

 

[sasto]

Re: Sieving gas from tank?

I think we've already gone down the road of why gasoline and shop-vacs don't mix....

You bet...not with an acetone rag either, I know. I guess if there is a way for spark to exit the exhaust side of the vac, would be a bad idea. I am thinking theory more than actuality....Good day....Beefer.

 

[Beefer]

Re: Sieving gas from tank?

The pressure vs. vacuum got me thinking.....usually not a good thing. Could one block the vent, open the fuel supply line, and use something like a shop vac to apply pressure in the fill tube and force the fuel out the supply?

I think we've already gone down the road of why gasoline and shop-vacs don't mix....

I take back my last comment, sasto, thought you meant to suck it out... nevermind...

Yup, its a head, yup its odd.

ok, back to the head.... So Larson expects your (or anyone's) let's say, 16 year old daughter, or your mom, to lift the back bench, and do their business right there? Ummm....

 

[jeeperman]

Re: Sieving gas from tank?

ok, back to the head.... So Larson expects your (or anyone's) let's say, 16 year old daughter, or your mom, to lift the back bench, and do their business right there? Ummm....

Well they did mount it sideways. For an added bit of modesty.

 

[gss036]

Re: Sieving gas from tank?

I hate to say it, but this sounds like a disaster waiting to happen. If you have a manual hand pump, use that, not a 12volt pump, fume and sparks don't mix, they go kabooooom!!.
My old fuel tank that I replaced a couple years ago did not have an anti-siphon valve, but the replacement did. I used to just connect a female adapter to the fuel hose and start with the primer bulb and it continued to siphon fuel. Needless to say the new one won't do that, but I can use the primer bulb and pump fuel out that way, good hand exercise.
I have been thinking about attaching the old non siphon connection to the other threaded hole in the tank and put on a shut off vale so I can do that in an emergency. Mainly when I need gas to keep the generator running if we loose power or save a trip to the gas station for the lawn mower(tractor).

 

[paultjohnson]

Re: Sieving gas from tank?

If someone wants to pressurize the tank, why use a running shop vac? I would fill my air compressor up, unplug it so it wouldn't fire up and rig that to the gas tank.

 

[sasto]

Re: Sieving gas from tank?

If someone wants to pressurize the tank, why use a running shop vac? I would fill my air compressor up, unplug it so it wouldn't fire up and rig that to the gas tank.

If I remember correctly fuel tanks are factory tested something like 3psi..don't see why you couldn't use one with a valve and gauge though.

 

[paultjohnson]

Re: Sieving gas from tank?

If I remember correctly fuel tanks are factory tested something like 3psi..don't see why you couldn't use one with a valve and gauge though.

Wow really ?! Only 3 psi.. Glad I didnt try it then, I prob woulda put 20-30 lbs on and busted it wide open...Dang this forum is a good thing to have

 

[fishrdan]

Re: Sieving gas from tank?

I cringe every time I hear someone mention shop-vac and fuel tank, but I don't see a problem with what Paul did using the vac's exhaust. It's not like there is going to be enough fuel vapor out in the open air to cause an explosion.

To find the screws in the carpet (if there are screws), scratch around in the carpet with a standard screw driver. You will know when you hit one and they are easy to find by scratching around.

If someone wants to pressurize the tank, why use a running shop vac? I would fill my air compressor up, unplug it so it wouldn't fire up and rig that to the gas tank.

I'm guessing that boat has a plastic fuel tank. They are not supposed to be pumped up to over 3psi for testing and I doubt a shop-vac can go much over that. With an air compressor you would have a hard time dialing it down to 3PSI,,, without a low pressure gauge. I used an air compressor to test my tank and fuel system, but had to use a low pressure gauge attached to the vent line. At 3PSI the belly tank looked like the Michelin Man,,, I certainly wouldn't want to go more than that.