tank venting

[Mike4130]

So running the valve upwards works? I had someone tell me the valve needed to face down for the ball to be in the open position. Anyone else run thiers up like this with good results?

 

[Mike4130]

I think we've isolated the issue. It seems the the check valve doesn't work properly. It will allow air through it in both directions in & out. Thus allowing tank pressure to push fuel up the vent tube & out the defective check valve.

 

[Guest]

It needs to be 2 way. If pressure builds up in the tank it will flood the carb. If air can't get in you get vapor lock.

 

[Guest]

So running the valve upwards works? I had someone tell me the valve needed to face down for the ball to be in the open position. Anyone else run thiers up like this with good results?

I just use a filter. No valve.

 

[Dreggsta]

X2. You want the inside of the tank to have atmospheric pressure.

 

[Mike4130]

Well this brings up several issues then. Because the valve that came with the kit only allows air to be sucked through it, not out. The aluminum valve allows air both ways causing the vent tube to suck fuel up the tube and pump out past the valve.

 

[Guest]

How far in the tank is your vent tube?

 

[Mike4130]

How far in the tank is your vent tube?

Almost flush with the grommet. Nowhere near the fuel. That's whats confusing!

 

[Dreggsta]

Silly question but are you filling the tank up to the grommet? If there is no fuel to the tube then fuel can't be going through it.

 

[sanos]

I don't know why you guys are using this type to vent your tank. There is nothing to slow down the rate of gas coming out in a turn-over. The gas cap have it already.

 

[Mike4130]

Silly question but are you filling the tank up to the grommet? If there is no fuel to the tube then fuel can't be going through it.

We ran the truck almost out of gas, and it still sucked fuel up the tube. So it wasn't near the vent tube.I understand what you're saying, I can't understand how it's reaching the tube either!

 

[Mike4130]

Here's a pic of the tubes installed. Should the return be submerged in the fuel or does that matter?

 

[Dreggsta]

Maybe it's splashing around getting to the vent. What you are saying is mind boggling. Well, I ran my vent to the cap & I haven't had this issue thank god lol. Try removing that aluminum piece & putting a small engine fuel filter on it. Should be like $2.

 

[Mike4130]

I know! Gas fills the tube and just pours out. No idea...Now if I use a vented cap, no problems. But, the engine bogs because of low fuel pressure I'm assuming.

 

[Dreggsta]

What you are saying about the engine bogging & low fuel pressure could be from the carb. Either the tune like the lsn or something else with the carb? Also, silly question again, you don't have lines crossed do you?

 

[Mike4130]

Nope, triple checked the lines. Feed to the bottom of carb, return on the top.

 

[Dreggsta]

Here's a pic of the tubes installed. Should the return be submerged in the fuel or does that matter?

return to the top like it is. Not submerged.

Idk man. Hard to help w/out seeing it in person. Try pulling the vent line up some more so it's not flush w/the return line. Also I recommend putting a loop in the vent line & putting a fuel filter on the end. The loop will act like a p trap sorta & catch some fuel. The filter will keep contaminants outta the tank bc remember, the vent breathes air in.

 

[Mike4130]

I certainly appreciate all of your recommendations Dreggsta.

 

[Shalako]

You just need to add a vent tube into the tank or to the fuel cap. For the cap you can just pick up a threaded nipple at your local haredware store. Drill a small hole into the cap and thread in the nipple. Run a piece of fuel tube up the rollcage and down to the chassis.

For the tank you can drill a third hole in the grommet and insert the tube about 1/2 incn into the grommet. Route the tube up and down to the chassis.

Here are two of mine. I prefer to add the tube to the tank, but the cap mod is easier.

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RCDAD:

Those brass fittings going through the grommet, did you insert them into hose and then put through the grommet? They are probably too thin to seal in the holes in the grommet correct?

 

[Guest]

That is correct. On the MT (second pic) I used a piece of fuel tubbing on the fitting to make it tight.

On the XB (1st pic) I added a third hole to the stock grommet, so it fit tight without adding fuel line.