newbie with gas flow question

[rickcarl]

Hi all,

Just got a 73 Bronco and love it but am having problems figuring out the two-tank system. How do you switch between tanks? There's a toggle on the dash and a **** below the driver's seat. The gas gauge doesn't work so I'm trying to figure out what works. Basically, lately the Bronco is sputtering and dying. Switching from one tank to the other (using the ****) doesn't seem to change the sputtering. What could it be? The tanks or something entirely different? Am stumped. It would seem to be the tanks but maybe it's something between the tanks and carb. I dunno.

 

[Bully Bob]

Hi Rick.., welcome..!

This is common with ev. EB purchased. Very likely one or both tanks were contaminated with "stuff." Adding fuel moves it around & it heads to the carb. (or plugs the pick-up tube)

Prob. got some debris in the needle & seat.., or in the main jet, or idle circuit.

Always put a glass see-thru fuel filt. B/4 the carb. on a newly aquired older veh. especially if it sat for a while.

If you serv. the carb. DEF. put good filt. there or you'll go thru the same thing over & over.

Poss. you may need to clean the tanks & lines at some point.

--OR--

Could be an ignition issue... Have you insp. the dizzy, plugs, wires, connections.?

 

[rickcarl]

Hi Rick.., welcome..!

This is common with ev. EB purchased. Very likely one or both tanks were contaminated with "stuff." Adding fuel moves it around & it heads to the carb. (or plugs the pick-up tube)

Prob. got some debris in the needle & seat.., or in the main jet, or idle circuit.

Always put a glass see-thru fuel filt. B/4 the carb. on a newly aquired older veh. especially if it sat for a while.

If you serv. the carb. DEF. put good filt. there or you'll go thru the same thing over & over.

Poss. you may need to clean the tanks & lines at some point.

--OR--

Could be an ignition issue... Have you insp. the dizzy, plugs, wires, connections.?

I'm guessing it's not the tanks themselves since the PO said he had them replaced. But I'll check the rest. Thanks.

 

[Purcell]

Sorry, haven't been around for a while, the switch on the dash only controls the fuel gauge/switching between the tank under the drivers seat and the rear tank tucked between the frame rails. The valve under the seat controls the fuel flow from the tanks to the Carb. If both tanks have fuel the the problem is most likely the fuel lines or the fuel filter at the carb. This is hard to bypass because it has a threaded fitting on one end and a hose barb on the other. I would replace this filter with the correct one and put a clear one in just ahead to see what is being sucked in the lines.

hope this helps

 

[rickcarl]

Sorry, haven't been around for a while, the switch on the dash only controls the fuel gauge/switching between the tank under the drivers seat and the rear tank tucked between the frame rails. The valve under the seat controls the fuel flow from the tanks to the Carb. If both tanks have fuel the the problem is most likely the fuel lines or the fuel filter at the carb. This is hard to bypass because it has a threaded fitting on one end and a hose barb on the other. I would replace this filter with the correct one and put a clear one in just ahead to see what is being sucked in the lines.

hope this helps

Thanks guys. But one more question. The valve under the seat--which direction you turn it corresponds to which tank? I would think to the right is main tank and left is aux to match the toggle on dash. Is there an off position too?

 

[Bully Bob]

"The valve under the seat--which direction you turn it corresponds to which tank?"

Anybody's guess if any PO's changed the hoses & switched them... once you find out., Mark them.

Orig. I think the pointie end (not the handle) points to trannie tunnel for main.

& I think pointie end pointing down is off.

 

[Bronc76]

On mine (and yours should be the same) the long part of the handle should be pointing to the right towards the tranny for the main tank, but like Bob said you never know what the PO may have done. There should be plate behind the switch that should say MAIN/AUX.