Now The Carb Isn't Getting Fuel...are You Kidding Me?

I just replaced the water pump and everything SEEMED fine...now all of a sudden I'm not getting any fuel in the carburetor. Did I mess something up that bad???

The fuel line and fuel filter were replaced in the spring when I got the Jeep running after it sat for 6 years. Pretty sure it's a mechanical fuel pump.

So when I push the gas I'm not getting any fuel squirting into the carburetor. And yes, the tank is full.

Ugh. Help!

 

I'd say the mech pump has given up on you? If you disconnect the fuel delivery hose from the carb and have someone crank the motor do you get fuel squirting out? If you don't I'd say you've found the problem. If you do then it could be a stuck valve in the carb.

 

Candace you need to determine what you have in your fuel delivery system. Some guys have installed an electric assist pump in line with the mechanical pump. Take some pictures of the complete fuel line from mech pump to the tank and post.

 

I would do this first. Be very careful to catch the fuel safely.

You need two things - sufficient volume delivered, and adequate pressure. Those are two different things.

 

Fuel pump is a pretty common failure; Jeepers used to always carry a spare.

If you disconnect the hose, don't let the spurting fuel go everywhere. Use a cup or a jar to catch any fuel. Disconnect the coil wire from the distributor cap and clamp it to metal on the engine - no start, no sparks!

With any no-start condition, it's always fuel or spark, and then divide and conquer. Look for where the fuel stops, and that's your problem. There is a hose between the steel line on the frame and the fuel pump. disconnect that at the fuel pump, hold it lower than the tank and fuel should flow out. No fuel from the pump, fuel available before, pump is bad.

I would mention - this car is nearly 50 years old. Old is old, even if it's not worn out. Idleness causes problems of its own. You are going to have occasional trouble with it, even if you get everything in top shape - you can't renew everything, and you cannot predict every problem. Hopefully you'll get past the immediate problems and issues will become less frequent. You will need to spend time and money for parts and repairs.

 

I think there was an electrical pump, too. I vaguely remember my (now ex) husband having me disconnect it like 15 years ago. Does it need both?

I'll have to google where the fuel pump is and what it looks like. Ya. I don't know. I feel stupid and super frustrated.

 

Someone told me accelerator pump on carb. You think it would be the fuel pump instead? I swear I did the accelerator pump a few months ago. It was attached to the front of the carb? It was leaking.

I will google what the fuel pump looks like. I feel so stupid.

 

I'll try that, too. I did look in the carb with the air filter off and when I pushed the gas no gas squirted in there.

 

I do appreciate your patience with me. I know I probably shouldn't even be attempting to do any of this myself since I have no clue what I'm doing. There's no way my water pump replacement would have messed up something with the fuel delivery, right? I'm just second-guessing everything I've done now.

 

If you have gas in the float bowl, likely the fuel pump is working. Pull the hose off at the carb and you should see some drops of gas in the hose. If it's completely dry, I'd condemn the fuel pump first. If there is gas at the carb connection (fuel filter out), see if cranking the engine spurts gas. There is a spec in the TSM for how much pressure the fuel pump should be delivering. You would need a pressure/vacuum gauge to test that (not expensive on Amazon) but you can do the spurt test if you don't have a gauge. A good fuel pump should deliver like half a jelly-jar of gas in say 10-15 seconds of cranking.

Be sure you ground the coil wire so there is no fire from a spark and the engine can't accidentally start and run you over. Really.

The accelerator pump is one of those things that is likely to fail after long idleness (as is the fuel pump). You understand that it's the accelerator pump that delivers the squirt of fuel that you can see in the carburetor throat? There is an accelerator pump diaphragm, and small rubber one-way valve in the side of the float bowl. Both have to work for the accelerator pump to squirt. If the accelerator pump is ok and the fuel pump is bad, you can connect a can of gas sitting on the cowl, make a siphon, and the engine will run just from siphon pressure.



Fuel pump failed on my J20 in 2016. I drove it into the garage using my mower can and a piece of fuel hose. Note the carb won't draw-in the fuel; you need to start a siphon in the hose before you connect to the carb. Siphon pressure is enough. Be sure to securely plug the outlet from the failed fuel pump, in case it starts working.

 

Nah, you're doing fine. Just keep going. It's a hobby car - don't let it get you down.

 

This is correct. Common problem. They often leak after sitting for years.

Driver's side of the engine, at the front half-way down.

More Information for SPECTRA PREMIUM SP1077MP

 

Is the gauge/tester thing I need? The instructions on the box say it tests fuel pressure...

 

Bingo!

Mac is a good brand too, one of the tool-truck brands that has salesmen that drive around to sell to professional mechanics.

 

Ya. My husband was a mechanic. He left most of his tools here.

 

This is the mechanical fuel pump. If you have an electric fuel pump in addition, it would probably be back near the gas tank, on the inside of the frame rail. Electric pumps sometimes can be used in addition to a mechanical pump. If present, you would hear a clunk-clunk-clunk or whirr when the key is turned on. They make noise until pressure builds, then they automatically stop until there is again demand for fuel pressure.

 

Welcome to the club.

That's how we all started, and still true every time we face a new challenge. But along the way you accumulate background knowledge, skills, and tools.

 

And scars, and parts, and debt, and...