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Discussion Starter · #1 ·
Greetings, I apologize if I'm in the wrong section.

I have a kit car. It's on a 69 or 70 frame with a 70 or 71 engine. 1929 mercedes ssk.

Single port, generator.

I'm running an external fuel pump that's giving me 3 or 3.5 psi. It's back in my engine bay. My fuel tank is a square style sitting up front.

The car was doing great until last year when I pulled off the original air filter and also put an aftermarket exhaust on. Then it did great for a few weeks, then the problems began, and then winter hit. So I'm dealing with it now.

I replaced my little fuel pump that's by the engines electric, external. The original mechanical one is still there, and it works, but nothing is hooked up to it.

Fuel tank pumps out the top of the tank, so there is some sort of pump in there that pushes out a little fuel.

Car will start and idle, but it's a rough start until you give it a little throttle.

Car dies when under a load, I can get about halfway around the block before it dies completely or dies when I stop or let off.

Is it my carb? Fuel issue?
45161
 

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67 Bug. 2275cc, 10.1:1, 48IDA,Eagle2242Cam,2300Lb clutch, 3.85 diff. Lowered,roll bar, 5pt, swaybars
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If the fuel tank has a fuel filter, I would check this. Check any other fuel filters in the back.

The easiest place to start is to remove the air cleaner and look down the carb at the throttle plate. Use a flashlight if needed. Open the throttle slowly and look for a good constant spray of fuel coming from the accelerator pump nozzle (brass pipe pointing down). Try it a couple of times but no more or the engine might flood. If little fuel comes out, either the accelerator pump diaphram is defective, the pipe is clogged or there is very little fuel in the float bowl. Try this first as it is easy.

Next I would try removing the fuel line coming from the front tank to the second pump at the back, and check to see how much fuel is coming out. I would suggest you put the car in neutral and push it back and forth a couple of times so any water in the tank gets mixed with the gas. Use a quart or 1/2 gal glass jar to see if a good supply comes out when the pump is running (don't crank engine). Also let the fuel sit in the jar a minute or two and see if you are getting water and that the fuel is clear (no rust). Next step is to connect the fuel line to the second pump and repeat the test using the fuel line that is connected to the carb. Check that you have a strong stream of fuel coming out of the line. If you have good fuel pressure and a strong flow, then the carb needs a second look. If fuel pressure is low or the flow is low, you have a clogged fuel line or filter. When replacing the fuel line on the carb, make sure you have good hose clamps on each of the rubber fuel lines. The fuel lines can come off the metal pipe on the side of the carb and start a fire. Also keep in mind that most gas has ethenol in it which can attack rubber fuel lines and rubber parts used in older carburetors and fuel pumps.

If you have good fuel pressure to the carb but the engine starves for fuel, there may be a clog in the float bowl needle valve or some crud in the bottom of the float bowl. It is possible to take off the top of the carb and look, but better to take the carb off the engine and then take the top off to look.

This is a good place to stop until you can tell us what you have found so far.
 

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67 Bug. 2275cc, 10.1:1, 48IDA,Eagle2242Cam,2300Lb clutch, 3.85 diff. Lowered,roll bar, 5pt, swaybars
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By the way, another check when you have the air cleaner off is to turn on the pumps and look for fuel dripping into the carb with the engine not running. If you see fuel dripping onto the throttle plates, the card is flooding the engine.
 

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You don't necessarily have a puml in the tank. External fuel pumps suck fuel from tank. If rubber hoses leak before pump you won't have enough suction.
 

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Discussion Starter · #5 ·
I appreciate all the feedback! Once it warms up next week I'll take another stab at it.
 
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