gas flow curiousity (lack of)
 

The 1931 Closed Cab truck would not start this morning. (This is newly rebuilt engine that has ran in the past but has sat for about 6 weeks since my family and work kept me away from the old cars and the garage.

I checked for spark (strong), timing is good, lots of air, but no gas. I have an electric fuel pump that feeds the weber 32/36 dgv carb on the 4 banger engine. As an experiement I took off the glass sediment buld and drained it, reintalled it with the rubber gasket and wire mesh filter to see if when the gas valve was turned on it would refill. To my surprise it would not refill. So I loosened the nut on the bottom a bit and the gas flowed filled the glass bulb and began to leak outside the assembly. I tightened the bottom nut tnad the gas flow stopped again.

My questions:

I am I wrong to have a rubber gasket on top of the glass bulb?
I have seen cork gaskets for the assembly, might it work better, provide a good seal but allow gas to flow?
Has this happened to anyone else?

To make sure I had good flow during th experiment, I tries it with the gas cap on and the gas cap off, both with same results. The gas tank is half full of new gas. The flow was tested with and without the fuel pump running and when the nut was tight no gas flowed.

Thanks, Dave

Re: gas flow curiousity (lack of)
 

Dave,
Do you have a 'filter' attached on top on your shut off valve , inside tank?
Have you ever cleaned your tank and/or know that you have a clean tank?

I ask these questions, because with a 'fuel pump' you may have 'pulled' some sediment into the valve. If you have the micro screen, you may have pulled some crud into this screen. Next time this (no flow) happens, gently blow back thru valve with tank cap off. You should hear bubbling and gas should then flow again. And, if any of this is so...corrective action ?

Re: gas flow curiousity (lack of)
 

Sounds like there is a blockage past the bulb. Could be the carb float stuck.

Re: gas flow curiousity (lack of)
 

if I understand it, you have a simple air blockage, and loosening the thumb screw under the filter permits air out and permits fuel to flow, filling the void.
I have a 57 thunderbird type glass bowl filter on my late 31 "original" type fuel system, and I have to bleed it each time I remove the filter for cleaning or whatever.

Re: gas flow curiousity (lack of)
 

Many electric fuel pumps have been built with rubber parts not intended to be used with 10% ethanol. Given a chioce of rubber gaskets or cork gaskets, I'd use the cork.

Re: gas flow curiousity (lack of)
 

What happens if you take the glass sediment bowl out of the equation?? Does ther pump pump then??
Paul in CT

Re: gas flow curiousity (lack of)
 

Frank has it right. There is a blockage past the bulb which won't let the fuel and air flow. When you loosen the bulb the air flows out the seal and when it is tightened it stops but the fuel cannot get past the blockage. Check the float or the needle and seat.

Re: gas flow curiousity (lack of)
 

Tom is right. Ethanol blended gas attacks most rubber parts and they swell up. My guess is that if you check the fuel pump or pressure regulator (if you have one) you will find a swelled up rubber part. Mr Gasket pressure regulators do not stand up to gasahol.

Re: gas flow curiousity (lack of)
 

I noticed last night that downstream from the glass bulb, the rubber fuel line is mushy and and probably deteriorated and clogged the fuel filter in line with the fuel pump. I am going to take it all apart today and replace the fuel filter.

Thank you all so far for the advice. Based on what I am seeing you all are on the mark.

Re: gas flow curiousity (lack of)
 

Whoaaaa! :eek: Now we know the answer. That rubber line isn't made for garbage gas. I'd try to use only a steel line.

Re: gas flow curiousity (lack of) additional info
 

Today I replace the fuel filter, and the fuel lines from the glass bulb to the carb. Prior to attaching the new fuel line to carb I ran the fuel pump and the gas flowed very well. I then attached the line to the carb and tried to start the truck. it would not start, and I could not get fuel to squirt into the bowl of the weber 32/36 dgv carb. I think there may be something inside the carb prevent the gas from flowing.

Any ideas are greatly appreciated.

Dave

Re: gas flow curiousity (lack of) additional info
 

Dave,
Hmm, new info. Ok, do you have a 'ferral' on the end of the gas line that enters the carb? If so, check that this 'ferral' is not set back tooo far on the gas line. If it is set back too far, the gas line may be protruding too far into the inlet and blocking/preventing proper needle/float operation. Also, float may have stuck in the (up) 'shut off' position. Easy to check(at least on a stromberg)just remove screws and lift top off. Also, some foreign object may have blocked the needle (inlet)area.