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1938 dodge fuel pump question


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hi all

any help on fuel pump no gas getting to carb have fuel to pump but nothing going in to line up to carb blew out lines gas is coming to pump took pump off is the level suppose to real hard to push down or is suppose to work up and down freely any help welcome p.s. bowl on rear of pump was full

thats john

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Kinda hard.

Unhook the line at the pump that goes to the carb. crank the engine, you should get good strong pulses.

Also make sure that the gas you see from the tank will flow freely.


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Essentially some of the same problems I have been having on my '36. The pump is similar.

First, my long time working pump finally failed by having the rubberized surface of the diaphragm get dry and turn to a powder about the size of sugar crystals. This stuff went into the carb and was causing periodic running problems that were hard to chase down initially. Then, the diaphragm finally failed enough by becoming porous and letting gas through so that there was fuel leaking through the weep hole in the underside of the diaphragm chamber. At this point the pump would not create enough pressure to get the fuel to the carb.

Second, I took this pump off and replaced the diaphragm with a modern alcohol fuel resistant replacement. I had help replacing the pump because I could not get my "large' self around the manifolds and between the fender inner wells to get one of the mounting bolts back in. I think what happened next was that the lever arm got "below" the cam instead of "on" the cam and when the first attempt was made to start the car after remounting the pump we heard a POP. No fuel was moving. The line to the tank was checked and OK. But there was still no gas out of the pump. We removed the pump again and found the lever arm had sheared off at the fulcrum point! That was the POP sound.

Third, took this pump off and replaced it with a pump that was purchased as a completely rebuilt pump, probably done as long ago as the 1960's or '70's. There was a certain stickiness all the way around the diaphragm area on this pump. I did not want to open it and lose any seal made years ago. I needed to get to a show the next day so in it went. The same helper was made well aware of the issue with mounting the pump so we made sure it was in place. All went in well. We started it right up! The car was running well. We went for a test drive in the dark. All was well. I went to the show the next morning and had a great time! Absolutely no problem driving there. The car sat at the show for 7 hours. When it was time to parade out of the show, everyone was starting up and heading out. My car started and ran out the gas in the carb then quit. There was no start after that. I pulled the fuel line from the carb and no fuel was coming from the pump! While the line was off I pulled the inlet seat to the carb and found the needle was stuck to the seat with some kind of black goop that had hardened during the day. This was probably some of the sticky stuff I saw on the edges of the diaphragm that had gotten inside the pump. The "now-a-days" fuel liquefied it while driving to the show but it solidified again while cooling down and sitting idle at the show. This stuff probably stuck the pump's valves shut too! Hence the lack of fuel flow after the show. I haven't had a chance to look into it yet specifically but the evidence was there with the needle stuck to the seat in the carb.

A side note: I always fill with mid grade non-alcohol fuel from our local farm supplier. I have been avoiding alcohol fuel, since it came out, in my old cars.

These may be a few things to think about in your specific case.

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