| james whitten | -- 08-22-2012 @ 1:58 PM |
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ihave tried 3 new fuel pumps, with no sucess after the car sits over 3 weeks, the engine will start after times pouring gas in the top of carb.
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| 40 Coupe | -- 08-22-2012 @ 4:28 PM |
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Take electrical tape to the joint of the body of the pump and the metal cover, then try to see if the pump will prime the carb. It may take about 30 Sec of turning over. If so the gasket between the body and the cover is leaking vacuum and preventing the pump from drawing fuel to the pump. Replace the gasket and check the V8 Times for the ad for the flex fuel line with a check valve. This may help but expect to have extended first starts if your only running the engine every few weeks.
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| Gail Rodda | -- 08-22-2012 @ 4:36 PM |
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I would put a electric fuel pump just in front of the gas tank.Hook it up to a switch under the dash so you can shut it off after the car starts. Let the pump run untill it pumps gas up & fills the carb. & shuts off.The gas is draining back to the tank after setting for a while & also evaperates out of the carburetor.
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| supereal | -- 08-22-2012 @ 5:02 PM |
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I have to have explained why a check valve between the pump and the tank is necessary. The fuel pump has a built in check valve. If the tank is properly vented,there can be no "drain back". There are lots of old pumps out there. If you have insufficient fuel at the carb, suspect the fuel pump or a partially obstructed fuel line to the tank.
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| TomO | -- 08-23-2012 @ 8:14 AM |
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James, 40Coupe has the right idea about a vacuum leak being the problem with the fuel pump not priming. You did not state which fuel pump that you are using. Are you using the stock 36 fuel pump that has been rebuilt, are you buying new fuel pumps from Airtex that replace the 41-46 pump or does your pump have a glass sediment bowl? If you are buying new Airtex fuel pumps, try the Offenhouser fuel pump from Speedway. Also try a new flex line and make sure that all connections are tight. If you are using a rubber gas line from the tank or have a filter spliced in the line from the tank, these could also be the reason that the pump will not prime. The flex line with the valve in it requires that the gas tank and line be completely clear of any debris. If there is any debris in the gas, the valve will not work according to the literature that I received with the flex line. The gas in the carburetor bowl will disappear over a 3 week period, so you will have to choke the carburetor in order to draw some gas into it. Tom
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| 51f1 | -- 08-23-2012 @ 1:01 PM |
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Supereal: You need an extra check valve because folks rather add unneeded stuff and modify their old car than fix the problem. Converting to 12 volts is a prime example. A properly maintained Ford 6-volt system works just fine. A properly maintained Ford fuel system will work just fine too. But you already knew that. Richard This message was edited by 51f1 on 8-23-12 @ 1:02 PM
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| james whitten | -- 08-23-2012 @ 6:32 PM |
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tom o,I have tried 3 new pumps, 2 from carpender @ 1 from c&g parts. They are copies of the original.the 36 has a new gas tank, new copper line, no filter,and i tried the flex line with the value. also put new push rod under the pump.j w
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| TomO | -- 08-24-2012 @ 8:08 AM |
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Now that I have the details, I suspect a vacuum leak in the supply side of the fuel pump. Ford soldered the ferrule onto the gas line to reduce the chance of a vacuum leak. You can do the same. When you remove the tank end of the line, carefully examine the ferrule to ensure that it was crimped evenly when you tightened it. If it was not, trim it off and install a new one. I would not use the flex line with the valve. You should also check the fuel pump vacuum with a vacuum gauge. Here is an excerpt from my V-8 Times article: Failure to prime: There have been many complaints about gas evaporating from the carburetor when the vehicle sits for more than a week. This means that the fuel pump must prime itself and pump some gas into the carburetor before the engine will start. The Ford V-8 fuel pump must be able to generate and hold vacuum in order to draw the gas from the tank and lift it as much as 18 inches to the sediment bowl. Once the pump is primed, the pump must deliver gas to the carburetor. The source of the vacuum is the diaphragm and the input valve acts to hold the vacuum. A good pump will prime itself in about 30 seconds and start the car in about 60 seconds. Add about 30 seconds of time to fill the glass sediment bowl. Do not crank your car continuously for this length of time or you will burn out the starter. If you are having a problem with priming the fuel pump, hook a vacuum gauge to the input of the fuel pump and crank the engine. The vacuum gauge reading should rise to 10 inches in 18 seconds. Stop cranking the engine and watch the needle on the gauge. It should take at least one minute to reach 0. In order of probability causes of failure in this area are top cover or sediment bowl gasket leaks, input valve not working or defective diaphragm. The valves in the new after market pumps made by Air-Tek will not hold vacuum above 5 inches. This may lead to priming failures. The valves in the pre 1941 fuel pumps are more likely to fail than the later type. If the above test showed that the fuel pump was OK, move the gauge to the next connection in the input side of the fuel pump and retest. This will check out the flex line and the connections to the tank. If these tests results show good connections, the problem could be plugged lines or tank pickup. A bad connection may not leak fuel, but it will leak vacuum. The flex lines can leak at the crimp for the connection or from pinholes caused by not being alcohol resistant Tom
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| supereal | -- 08-24-2012 @ 8:30 AM |
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This problem can arise when the pump stand, manifold and/or the pump rod isn't correct for the vehicle due to changes over the years. If it ran before the pump was replaced, be sure that the replacement pump is, in fact, the same, even if not for the year of the car. A common problem with old Fords is that while parts may appear identical between years, there are often slight differences that make interchange tricky. Over the years, it was usual to head for the nearest junkyard for engines and parts, particularly during the war years, causing problems for the unsuspecting. We have run into these problems more than expected. It is complcated because vendors often use faulty interchange info.
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| Gail Rodda | -- 08-24-2012 @ 1:33 PM |
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I have been A ford mechanic for neerly 60 years & I have several antique ford cars & work on alot of my friends cars. The only cars that will start after setting for several months are fuel injected cars guess where the fuel pump is ( electric in the fuel tank) if you are replacing orignal style fuel pumps to stop them from draining back when setting A long time good luck.
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| supereal | -- 08-24-2012 @ 2:38 PM |
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That's why many of us, including me, have an inline pump just outside the tank to allow refilling the carb after long periods of inactivity. I turn mine on, wait a minute or two, then pump the accelerator, and it starts on the first crank. It greatly reduces the cranking time, saving the battery. I still don't buy the "drain back" idea. The real reason for a dry carb is the "heat soak" after the vehicle is shut down. This causes evaporation of the fuel in the carb bowl. It became more of a problem when today's gas changed the "vapor pressure" of the fuel, allowing rapid loss when in the presence of heat. The inline pump, from C&G, is less than $70, complete with connections and filter, and will cure the "vapor lock" and "drain back" complaints. It is also a "belt and suspenders" backup if you have a fuel pump failure, a common problem with today's fuel.
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| Stroker | -- 08-24-2012 @ 3:27 PM |
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As a lad growing up with a fleet of flathead-powered agricultural Ford trucks and equipment, we kept an inventory of fuel pump inlet hoses, since that was usually the first thing we changed when things refused to start due to fuel delivery issues. The worst offenders were the expensive aftermarket "racy looking" ones with metal braid, as they would dry and crack inside, and look really good on the outside, while leaking air like a sieve. I'm with Super and Gail on the hose anti-drainback check valve. I see no advantage to it if everything else is OK. Most of these hoses fail by admitting air into the hose which pretty much destroys the vacuum that the fuel pump is trying to generate. The maker of the advertised "check-valve" hose also makes a very good modern fuel resistant stock-appearing hose without the check-valve, which I use. I also have an electric fuel pump on my 38; an ancient Bendix 6V-Pos. ground with a cleanable screen. I wish they still made these, as they were very reliable, and were used in many aircraft applications. A really good design, and just noisy enough to not forget to turn them off. This pump has been in-place* for 56 years, and I'm hoping a few more. * no, it hasn't been run continuously for 56 years. This message was edited by Stroker on 8-24-12 @ 3:40 PM
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| Gail Rodda | -- 08-26-2012 @ 10:03 AM |
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If you put A electric fuel pump on buy A gear pump. the first one I used was A diaphram type the car set A while & the diaphram turned to mush because of the ethynol in the gas. I also try to get 100% regular gas.
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| TomO | -- 08-26-2012 @ 11:03 AM |
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I use the fuel pump with the glass sediment bowl and it will prime with about 30 seconds of using the starter in 10 second bursts and full choke after sitting a couple of weeks. Connections to electric pumps seem to cause as many problems as the pumps fix. Tom
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| supereal | -- 08-26-2012 @ 11:17 AM |
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Most of the problems with inline electric pumps are caused by using the spring type clamps usually supplied with the pumps. Always use the worm screw clamps. We install barb fittings on each end of the original fuel line. Trying to seal a rubber hose on a non-barbed metal line depends on whether the line and hose are correctly sized. A hose that is just a bit too large will pucker and admit air. The barb fittings use a ferrule to seal to the metal. The clamp should be position behind the barb, not on top of it, as we often see. I've had an inline pump from C&G on my '47 for over ten years, after a Delco pump was ruined by alcohol in the gas. I use a spring loaded switch so I don't forget to turn the pump off after priming the carb.
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| Oldad | -- 08-26-2012 @ 1:42 PM |
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Supereal, I take it your electric pump does not interfere with the flow of fuel when it is turned off. I bought a car with a failed electric pump, close to the tank and inline, with the mechanical pump. I removed the failed pump and found it difficult to blow through, indicating it was restricting fuel flow to the mechanical pump. I looked at the electric pumps at the C&G site but there was no information on free flow in the off position.
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| Gail Rodda | -- 08-26-2012 @ 5:29 PM |
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I have several friends with electric pumps to prime the carb. They all let gas through when turned off. I like the idea of a spring loaded switch. I like this way to pump gas up to the carb. Pouring gas into the carb. could cause a fire.
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