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Need some help - 1934 Dodge DR Sedan starting problem

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Hi all - having a problem that I can't figure out and hoping someone has an idea how to fix it. I have a 34 Dodge DR Sedan that will only start without a blast of starter fluid. Cold or warm; choked or not, it will not start under any circumstances unless I give it a quick squirt of starter fluid, and then it starts right up. I have even tried 100 octane gas with and without lead substitute. Any ideas?

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Thanks,

Dave

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I have been messing with my car for a while now with very similar troubles. I did seem to find that the carb bowl dries out very quickly. I think it has something to do with the gas volatility now-a-days. The carb seems to run dry very quickly after turning off the engine from the heat coming up from the exhaust manifold. I have been giving this idea a line of thought recently. What do you think?

I do not think the 100 octane gas would help - it may even cause more trouble with volatility. Lead additive really has nothing to do with this. BTW: Aren't the valve seats on the '34 hardened like on the '36? There would be no need for extra lead unless pulling a trailer under load, driving at high speeds consistently, or driving in high heat (desert) a lot. I was even kicking around the idea of adding a bit of kerosene to the fill in an effort to change the fuel volatility. (But I don't think that would help much.)

Edited by 1936 D2
more data (see edit history)

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Before you try to start it take off the air cleaner and remove the top of the carb float. It's not too difficult. Your Carter/B+B carb top should come off with 4,sometimes 5,screws. The top of the carb will just lift off with the choke and it's cable still attached. There are no 'guts' in the top of the carb. The float chamber should be full,or nearly full,of gas. If not the problem is the fuel pump unless the needle valve for the float is partially stuck closed. The rubber tip does tend to rot after a while. Look at the fuel sediment bowl at the fuel pump. Is it full? I once had a similiar problem caused by the sediment bowl cork gasket drying out and shrinking and allowing the pump to suck air. The bowl would never fill up and the carb float bowl was never full either. Caused rough running and hard starting.

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When I have taken the top off the carb before, the bowl was empty and DRY. The fuel sediment bowl on the pump was full. Pretty sure it is not a fuel pump issue because it runs fine once started.

And actually just giving it a blast of starter fluid causes it to run long enough to get fuel into the bowl which then sustains it.

I am guessing that Dave's '34 problem is pretty much the same. Correct me if I am wrong please.

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I tend to agree with KLC. I have had this happen before and it was the needle valve seating. Interestingly, if the carb relied on gravity feed, the opposite would happen and the float chamber would flood. My guess is that the cause is ethanol in the petrol. Can you still get service kits for your carb? If not, a carb specialist will probably help.

Ray

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Hi Mark,

Yes, I'm in the Willow Glen area of San Jose. Call me at 408-265-4842.

Dave,

Are you in the San Jose area? Would like to come look at your car when I return to the Bay Area.

Cheers,

Mark

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Thanks all. I will try KLC's suggestion and look at the carb as soon as I get some free time. I should have mentioned that the carb was rebuilt 6+ years ago, but the car's only been driven about 200 miles since. Also the car is converted to 12V and has an electric fuel pump. Wouldn't that keep the bowl full?

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If anything, you would more likely have too much pressure with an electric fuel pump but the simple answer is no, it makes no difference and cars run perfectly well on either 6 or 12 volts.

Pretty sure it's the carb. You have checked for leaks I take it?

Edited by R.White (see edit history)

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Dave,

With an electric pump you should be able to fill the carb float bowl by just turning on the pump. This assumes you have no mechanical pump, or the mechanical pump is disabled so as to let gas flow through from the electric pump, or you have an electric pump designed as a priming pump to work in unison with a mechanical pump.

If the pump(s) are capable of delivering fuel to the carb, then there is a carb needle / seat problem if the bowl is dry.

There are a lot of variables with an altered fuel delivery system. We would need to have the details of your current setup to accurately give other suggestions.

If the bowl isn't dry then there could be some sort of timing issue causing hard starts or some kind of rather large vacuum leak that is off balancing the carb.

These ideas and anything else would be guesses without knowing more info from diagnostic tests.

Toss us a bone as you get more info.

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Well, you really have me scratching my head on this one. Not owning a car like yours at this time, I can only speculate. I don't think it is the volatility of your fuel at all, having a no or low level of fuel in carb bowl. A few ounces of pure alcohol or pure gasoline in that carb bowl will not completely evaporate in a few days. Where would it go to? The throttle plate being closed, No way can the fuel evaporate out through the tiny vent hole. There HAS to be a leak, somewhere. If you say only a shot of starting fluid gets it going, Ok,--- that will not "un-stick" a faulty float valve, so I will count that problem out. The fuel must be leaking out through either a bad gasket under one of your carb jets, or a loose jet. Or of course, a cracked carb, but that would be quite obvious. Keep in mind, the carb float and the up-stream components have to be verified OK., like the fuel pump and it's internal check valves, pump diaphragm and the pump's push rod. Even the fuel line from pump to carb must be checked for tightness of the fittings and good shape, in the original configuration! I've seen problems arise with people varying from factory spec's and incorporating a loop in the line, now causing an air blockage with certain conditions.

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I think we are all scratching our heads on this one. My theory, for what it's worth, is that the problem is typical of what happens when the original system is adulterated instead of being repaired or serviced. As 1936D2 said, if the fuel pump is capable of delivering gas to the carb and the float chamber remains dry there must be a problem with the needle valve sticking shut and preventing it from filling the bowl. But where has the last charge of fuel gone? This is the strange bit. A poor seating allows the carb to flood.... KCL referred to a rubber tip which can perish but I am unfamiliar with this however, I would imagine it would cause flooding rather than starvation. Perhaps the pump looses it's pressure when left standing and allows the fuel to go back down the pipe and back fill the pump and sediment bowl.

I would go back to the original set up. Each to their own. The original system relied upon air pressure and gravity - with vacuum assistance.

If on the other hand, the pump is not providing quite enough fuel to the carb then this will manifest itself in rough running as fuel starvation causes misfiring and weak mixture. Left unattended this can cause burned exhaust valves resulting in low compression.

Chances are that there is a leak somewhere. My motto is "it's probably something simple" - (although this only applies to the pre - electronic age.) Just a few thoughts thrown into the mix.

Ray

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Dave: Can you post some detailed photos of your fuel routing, at least from any/all fuel pumps to the carb? And maybe a couple around the carb?

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Also Dave, some more photos of your car would be nice. We don't see too many of this model which I regard as about as good as it gets when it comes to styling.

Ray.

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Here are some more pic's of the car. I will take & post pics of the carb & fuel lines this weekend.

As far as suggestions of a leak - none are visible, plus the inability to start w/ gas alone is constant. Even if the engine has been running for a while, then is shut off and immediately tried to be restarted, it won't - unless starter fluid is used.

Thanks, Dave

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Here are some more pic's of the car. I will take & post pics of the carb & fuel lines this weekend.

As far as suggestions of a leak - none are visible, plus the inability to start w/ gas alone is constant. Even if the engine has been running for a while, then is shut off and immediately tried to be restarted, it won't - unless starter fluid is used.

Thanks, Dave

Nice looking car!

Shut off and then will not restart immediately without starter fluid. And when you check the carburetor float bowl it's empty? That is a bit of a puzzle.

By the way if you are in Willow Glen then I'm probably only about 10 miles from you. My '33 Plymouth probably has a very similar fuel delivery system (mine is stock). Let me know if I can be of assistance with on site diagnosis. I'm no expert but some times two sets of eyes will catch something missed by one set.

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Bill, I was thinking about that too, but if the fuel line at carb is dumping gas into bowl at a higher level than the float allows it to go, the fuel cannot siphon or run back out through fuel line when sitting or any other time. That's even if the fuel could get back through the float valve! I still hold in my opinion that the bowl is leaking is IN the carb, at the base of one of the jets. Either a loose or cracked jet or a bad gasket under one of the jets. The bowl would empty under gravity, given a short time, into the manifold where it goes unseen.---Pete.

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That certainly sounds like a distinct possibility, Pete. I am still trying to figure out why the gas could not return down the fuel line just enough to empty the bowl if the valve was not seating; that is assuming it is a bottom entry carb. The reason I thought this was because originally the needle valve would have been under atmospheric pressure (about 15lb psi) even when not in operation. The introduction of an electric fuel pump would mean pressure only when switched on - although residual pressure would exist but may be lost in a worn pump. If the carb is not a bottom fed type then your hypothesis would be correct as there would be nowhere else for the fuel to go.

Ray

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Yup, I agree Ray, We won't be able to go any farther until we get to see the carb and his set-up with lines and his pump(s). I think he's got a top feed carb, but who really knows as yet. As you must know, it's extremely difficult to cure a problem with just photo's. An owner must start with the basics, such as known good vacuum, gaskets, clean fresh fuel and tank also. When I hear that the stock design has been circumvented, I cringe at the thought of troubleshooting a problem "over the airways". I'm thinking that someone before him added the electric fuel pump, Why? Did the diaphragm fail in the mechanical pump? If it's an A.C> Delco pump, can it be possible for the gas to drain down, past a faulty check valve inside that pump, and dumping fuel into body of pump, whereas fuel would then drain into his crankcase.

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Say, Pete. What if someone has left out the gasket under the jet on a rebuild? Would that do it? I like this sort of puzzle - it gives me a chance to exercise the few little grey cells Iv'e got left! (chuckle).

Ray.

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If it's a top fed carb and the float chamber is found to be empty, I think there must be a leak because there is nowhere else for the gas to go. It's not likely, in my view, to have evaporated. If the fuel has leaked away there is no mixture to ignite. It won't fire up, so that's what the starter fluid is replacing. I would think that fuel having found it's way to the inlet manifold will get burned off, producing black smoke. Gas will be supplied to the carb as soon as the pump starts working which is when the ignition is switched on. Once the engine is drawing fuel through the carb it must be coming from the float chamber. What I can't understand is why the pump takes so long to replenish the float chamber?

Ray

Edited by R.White
me talking codswallop (see edit history)

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A slow leak from the jet will not necessarily flood the engine upon starting. Especially a hot engine whereas the leaking gas evaporates faster than any noticeable clue.One needs to remember, the float is there to set a level in the bowl, that is almost equal to the top opening of the jet! The starter turning the engine creates enough vacuum in the venturi for that instant to atomize the fuel and air,(faster with choke plate closed, of course), for the proper charge of mixture for the cylinders. If the bowl level is too low because of a leak, that initial vacuum won't pull the gas out of the jet, whereas the ether initiates starting and enough vacuum is created to get the bowl/jet to proper level. NOW---Is this clear as MUD??? The 1/2 to 1 ounce of leaked fuel in the manifold is just gunna sit there and evaporate a bit, not enough to vaporize with any air for starting this creature.

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