Bloo Posted June 22, 2021 Share Posted June 22, 2021 (edited) Be sure the test kit can do low pressures, and has fittings you can use on your car. Most kits are for fuel injected cars and are inappropriate. The old fashioned way to do this is with a vacuum gauge of the sort that has the needle out in the middle somewhere, and also has a pressure scale in the opposite direction of vacuum. 90+% of vacuum gauges you can buy are like this for the last 80 years or so. Tee it into the pressure side, in-between the fuel pump and the carb. If there is hose there you can just hook it up with a hose tee and clamps, if not you will need some brass fittings. Your fittings are probably inverted flare, but there might be some 1/8" pipe in there somewhere too, or even threaded sleeve fittings but I sort of doubt that. The tee should go to a smaller hose barb, as the vacuum gauge hose is smaller than fuel line by a lot. Clamp everything as good as you can. There may be no appropriate clamps for the small hose going up to the gauge. It needs to fit extremely tight on the barbs no matter what. If it doesn't, get a smaller hose. Better to clamp it also. Makeshift clamps can be made by wrapping picture wire around a few turns and then twisting it with pliers. I would look up both the 1936 and the 1953 fuel pressure. Which carb do you have? Which fuel pump? Make sure there's not a pressure mismatch between the pump and the carb. When you run it the gauge needle will flop all over the place when the pump runs. When the float valve shuts off the pump will stop pumping and you can see the pressure for a bit. Edited July 24, 2021 by Bloo (see edit history) Link to comment Share on other sites More sharing options...
Bloo Posted June 22, 2021 Share Posted June 22, 2021 You know what? Scratch that. I was just reviewing your pictures and that float needle has a groove in it. It is probably never going to shut the fuel off no matter what and you are never going to get a good reading. Try hooking output of the fuel pump directly to the pressure (vacuum) gauge and crank. It might give you a better idea of the pressure. 1 Link to comment Share on other sites More sharing options...
m-mman Posted June 22, 2021 Share Posted June 22, 2021 (edited) 1 hour ago, Weirdbeard said: Renting a fuel pressure test kit from Napa tomorrow Warning: Before you get it out the door make sure they know what you plan to do with it. Modern fuel systems are 50 or so PSI. They have screw on fittings. You dont need that and it probably wont register anyway. Old fuel systems are 3-8 PSI and use rubber hoses and brass nipple fittings to attach to. All you need are one of these old fashioned "vacuum" gauges. People dont always know that the needle swings both ways 20" or so of vacuum and 10 pounds or so of pressure. Edited June 22, 2021 by m-mman (see edit history) 1 Link to comment Share on other sites More sharing options...
JimKB1MCV Posted June 23, 2021 Share Posted June 23, 2021 I wouldn't be too concerned with the later engine on your car. At one time keeping the thing on the road was paramount and the wrecking yards had plenty of good used engines for not a lot of money. It might be a good idea to spend some time with Keith postings re his Chrysler products: His videos on YouTube may interest you as well. Good luck. 1 Link to comment Share on other sites More sharing options...
Weirdbeard Posted June 23, 2021 Author Share Posted June 23, 2021 4 hours ago, m-mman said: Warning: Before you get it out the door make sure they know what you plan to do with it. Modern fuel systems are 50 or so PSI. They have screw on fittings. You dont need that and it probably wont register anyway. Old fuel systems are 3-8 PSI and use rubber hoses and brass nipple fittings to attach to. All you need are one of these old fashioned "vacuum" gauges. People dont always know that the needle swings both ways 20" or so of vacuum and 10 pounds or so of pressure. Thanks for the info. Link to comment Share on other sites More sharing options...
Weirdbeard Posted June 27, 2021 Author Share Posted June 27, 2021 The specs I found said for a 1953 engine said that the fuel pressure should be between 4 & 5.5psi. I’m right at 4.75psi. so I’d say it’s ok. I’ll order a carb rebuild kit Monday from The Carburetor Shop. I still don’t understand why the fuel filter was dry when I originally broke down but the sediment bowl was full. That’s why I was leaning towards the fuel pump malfunctioning. I guess it’s a mystery. Link to comment Share on other sites More sharing options...
Weirdbeard Posted July 20, 2021 Author Share Posted July 20, 2021 Received the carb rebuild kit and also got a rebuild kit for the fuel pump. Now to find time to get them done! 1 Link to comment Share on other sites More sharing options...
keithb7 Posted July 24, 2021 Share Posted July 24, 2021 (edited) You have a good engine there. I have a 1954 25” long Canadian engine in my ‘38 Plymouth. It was 228 ci when new. I recently bored it over to 237 ci, stock Desoto size engine. No need to be concerned about the later year engine you have there, it’s very similar to the original engine. I suspect you likely have a 217.8 ci 23.5” long American engine. When your 1936 Dodge was new it also had a 217.8 engine, however it had lower a compression ratio. 6.5:1 Netting 87 HP. The 1954 engine had 7.0:1 compression ratio. Netting 97 HP. Edited July 24, 2021 by keithb7 (see edit history) 1 Link to comment Share on other sites More sharing options...
Weirdbeard Posted August 21, 2021 Author Share Posted August 21, 2021 Ok. Dropped off the carb for rebuild. Hoping to rebuild the fuel pump next week since this weekend is way too busy. Wondering if I should look into replacing the automatic choke since that would be the last item directly involved with the fuel delivery. Link to comment Share on other sites More sharing options...
keithb7 Posted August 22, 2021 Share Posted August 22, 2021 (edited) See info here on the choke system. Skip ahead of my rambing. Go to the 8 minute mark. Edited August 22, 2021 by keithb7 (see edit history) 1 1 Link to comment Share on other sites More sharing options...
Weirdbeard Posted August 22, 2021 Author Share Posted August 22, 2021 Great video! When I get the carb back I’ll have to investigate more. My manual throttle cable is missing the clamp and screw on the bracket. I’d like to find one sometime just to make it “right”. Link to comment Share on other sites More sharing options...
Weirdbeard Posted August 27, 2021 Author Share Posted August 27, 2021 (edited) Is there a way to replace the valves on the fuel pump cover? I don’t see any way to remove them since it’s a one piece cast aluminum. No screws to access anything. Edited August 27, 2021 by Weirdbeard Fuel pump (see edit history) Link to comment Share on other sites More sharing options...
Steve9 Posted August 28, 2021 Share Posted August 28, 2021 17 hours ago, Weirdbeard said: Is there a way to replace the valves on the fuel pump cover? I don’t see any way to remove them since it’s a one piece cast aluminum. No screws to access anything. I would just buy a new fuel pump. Pretty easy to find out there. Link to comment Share on other sites More sharing options...
keithb7 Posted August 28, 2021 Share Posted August 28, 2021 Super easy to rebuild. Modern pumps are pretty junky compared to good old made in the USA one you have there. In your photo you are missing 1 valve. The Other is there. Grab a screw driver pry it out. Tap in 2 new ones using a spacer. A deep socket the correct diameter is about a perfect driver. Be sure the 1 way valves are installed in the correct position. Suck and blow. In and out. Rebuild it! Link to comment Share on other sites More sharing options...
TerryB Posted August 28, 2021 Share Posted August 28, 2021 Check with Then and Now automotive for rebuild kits for your pump. Link to comment Share on other sites More sharing options...
Weirdbeard Posted August 29, 2021 Author Share Posted August 29, 2021 I did order a kit from Then and Now. It came with 2 valves that are “out”. The “in” valve possibly pops out but I don’t have a replacement. The “out” valve looks to be non serviceable as there is no way to access it. I don’t believe it’s missing, I think it’s internal and cannot be replaced. I left a message for Then and Now just waiting for a reply. 1 Link to comment Share on other sites More sharing options...
Weirdbeard Posted September 6, 2021 Author Share Posted September 6, 2021 Well I installed rebuilt carb and fuel pump. Issue is still there with no improvement. Can barely get it running and fuel pouring out carb bowl and back of carb by the linkage. Not quite sure what to do now. Link to comment Share on other sites More sharing options...
keithb7 Posted September 7, 2021 Share Posted September 7, 2021 (edited) The string of issues that keep appearing does seem a bit odd. Reviewing the thread here, you have had the carb rebuilt. Did you rebuild the fuel pump yourself? Car won’t run, and you have fuel pouring out of the carb bowl. You have 4.75 psi fuel pressure. Next I’d probably start stripping things down to basics. start fresh. What is each cylinder compression, cold? Hook up a dwell meter. Watch it while someone cranks the engine over. What dwell are you seeing? Pull all spark plugs. Lay them on the head, lead wires connected. Are they all sparking? Look at cap and rotor. Clean up at arc areas. All wires in place and all fasteners inside the distributor tight? How old is the condenser? Sparkplugs all clean? An engine can flash up even with all fuel lines removed. I’ve manually fed fuel into a dry carb myself to see if it will flash and run. If only briefly, at least you’d know it could run. Remove fuel inlet line at the carb. Attach a piece of fuel line to it . Put other end in a container. Crank over engine. Is fuel pumping out at a good rate? 4.75 psi seems a little high to me. I tend to be looking for the 3.5 psi range. Take cover off carb fuel bowl. Suck bowl dry of any gas with a syringe. Install about 2-3 feet of line at carb inlet fitting. Clear hose is nice for this test. You can see inside the hose. Hold line up vertically. Use a good sized syringe to put fuel into the temporary fuel line. Watch fuel bowl level in the carb. Is it filling up? It should be. Slowly filling. Watch the float. Is it rising? Keep add fuel to vertical hose. Watch bowl fill. Watch float close off fuel inlet valve. Fuel should now stop flowing from the temporary hose. No more fuel should flow into the bowl. Is this happening? Is the shut-off valve and float doing its job? Check your float level. What is it set at? Compare to spec. Set if needed. You only need a couple basic things to make your engine at least run. Fuel. Decent Compression. Spark at the right time. The carb just keeps the right amount of fuel going into the engine under various operating loads and speeds. You can replicate it for testing purposes. The engine won’t know any difference. Edited September 7, 2021 by keithb7 (see edit history) 2 Link to comment Share on other sites More sharing options...
Weirdbeard Posted September 8, 2021 Author Share Posted September 8, 2021 The strange part is that I drove the car for a couple weeks with no problems. The first fill up at the gas station and it immediately wouldn’t start. Coincidence? Not sure. I rebuilt the fuel pump as much as was physically possible with the kit. Screen, diaphragm and spring. After doing disassembling and doing some research, it seems that the fuel pump doesn’t control the fuel pressure at all. There’s no check valve or bypass of any kind. From what I’ve read the needle and seat control fuel pressure and flow. I’ve done the clear tubing with the bowl and the float stops as it should and seals with the needle. I honestly never thought to check for spark or compression. Seeing the fuel pour out of the carb. I figured it was a fuel issue. I can get it running by feathering the gas pedal as I hit the starter button. Runs really rough and stalls if I take my foot off the pedal. It does act as if it’s not running on all cylinders now that I’m thinking about it. Would that cause fuel to overflow the carb? Thanks for the tips! I’ll do more investigating and see what I find out. Link to comment Share on other sites More sharing options...
keithb7 Posted September 8, 2021 Share Posted September 8, 2021 I brought up compression and spark as I think there is possibly more going on here, than fuel leaking at the bowl. Please report back after more checks. Link to comment Share on other sites More sharing options...
Oldtech Posted September 8, 2021 Share Posted September 8, 2021 Fuel running out of the carb says one of two things. Either too much pressure from the pump, of float valve issues. The fuel pump controls the pressure. It is a function of the spring in the pump. The stronger the spring, the more pressure. 4.75 sounds a bit much. 3.5 lbs would be lots. but that would require a regulator. - which might be the answer. As for the carb, the only things that may be happening are that the float doesn't have enough buoyancy to hold the needle valve closed, the needle valve is defect, or fuel is getting in around the seat assem where it screws in. Or the float is way too high. ( looks ok in the pictures so I don't think so. ). If you could rig up a pressure test to put fuel to the carb with the lid off so you could see what is happening. This takes a bit of engineering but use an air tank with only 5 lbs in it and a line full of fuel. The answer may be obvious. Link to comment Share on other sites More sharing options...
Weirdbeard Posted September 12, 2021 Author Share Posted September 12, 2021 On 9/8/2021 at 12:29 AM, Oldtech said: Fuel running out of the carb says one of two things. Either too much pressure from the pump, of float valve issues. The fuel pump controls the pressure. It is a function of the spring in the pump. The stronger the spring, the more pressure. 4.75 sounds a bit much. 3.5 lbs would be lots. but that would require a regulator. - which might be the answer. As for the carb, the only things that may be happening are that the float doesn't have enough buoyancy to hold the needle valve closed, the needle valve is defect, or fuel is getting in around the seat assem where it screws in. Or the float is way too high. ( looks ok in the pictures so I don't think so. ). If you could rig up a pressure test to put fuel to the carb with the lid off so you could see what is happening. This takes a bit of engineering but use an air tank with only 5 lbs in it and a line full of fuel. The answer may be obvious. I was going to try manually holding the float down a little to see if I can regulate the fuel flow. It has a new needle and seat and float. I didn’t know the spring in the fuel pump was how it regulated the fuel. I’m still leaning towards to much fuel pressure as the float is maxed out all the way up. The gas then proceeds to fill the bowl submerging the float. This float is new and does not leak. The old one didn’t leak either but I figured it would be a good time to replace it anyways. I did the manual fuel fill with a clear tube and the needle seated everytime. Is it possible for the fuel pressure to be so high as to push past the needle even though it’s seated? I’m no carb professional at all but that’s what looks like is happening. If indeed that is the problem, is the solution a regulator, new fuel pump or a weaker spring for the fuel pump? When I ordered the rebuild kit from “Then and Now” I mentioned the problem I was having and they never offered a different spring as an option. Link to comment Share on other sites More sharing options...
m-mman Posted September 12, 2021 Share Posted September 12, 2021 (edited) 4 hours ago, Weirdbeard said: I didn’t know the spring in the fuel pump was how it regulated the fuel. Fuel pump basics - The diaphragm moves up and down to suck in and blow out the fuel. There are check valves that open & close insuring that the fuel moves the proper direction. The diaphragm is directly pulled up by the lever arm. This action creates a vacuum and draws fuel into the diaphragm chamber. The lever arm is them allowed to fall and stops pulling up on the diaphragm. (the lever arm does NOT push down on the diaphragm) The diaphragm is pushed down BY THE SPRING on the back side of the diaphragm. it is the SPRING that pushes down compressing the fuel and forcing it out toward the carb. If you stop the flow of fuel in the output line (plug it up) the lever will lift the diaphragm to draw in fuel. When it is released the spring will ATTEMPT to push the diaphragm down but it can only push with as much force as the spring has. (2 pound spring? 4 pound spring?) Because the spring cant eject the fuel, the diaphragm stays in the up position and the chamber stays full of fuel. The lever arm will come around again and lift the diaphragm, but because the chamber remains full of fuel no more is drawn in. So the output of the fuel pump can never be more than the pressure of the spring that is pushing down on the diaphragm. The lever arm does not push the fuel out. Edited September 12, 2021 by m-mman (see edit history) 3 1 Link to comment Share on other sites More sharing options...
keithb7 Posted September 12, 2021 Share Posted September 12, 2021 (edited) Yes, In theory too much fuel pressure would force the float down and sink it. Fuel spewing out any orifice it can. A great tool, a Mity-Vac vacuum & fuel pressure gauge. Awesome tool that will allow you to test many things. You can hook it up to your fuel pump and measure the pump’s output pressure. Indeed your fuel pressure seems high to me, as I mentioned above. You can get a Holly low pressure regulator. Pain in the butt really. You are better off to address your fuel pressure issue properly in my opinion. This same vacuum/pressure gauge tool can be used to set your air fuel mixture screw. Also set your ignition timing. Then you can also see a multitude of other things that could be going on in your engine. Here I am troubleshooting fuel pressure problems. Also dealing with a regulator that was added to my car’s fuel system. All gone now. I addressed the source of the problem. No more band-aides. https://youtu.be/W66Z6uYLcik Edited September 13, 2021 by keithb7 (see edit history) 1 Link to comment Share on other sites More sharing options...
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