Update on where I am at.

This morning I replaced the coil, igntion pickup, and I actually put a brand new ignition module on it since the one Viper gave me had some use under it. I figure either way-- its only about 75 bucks of new parts that it wouldn't hurt to replace.

Took it out for a test drive and less than a half mile from my house, it started to stumble... and then stalled. Had a couple of backfires and had a difficult time keeping it started to get home. I did however check the carb float level at the point of when it started stalling. I pulled over and was actually even leaning towards the float check screw. Took it off and started to rock the Bronco and I could not get any fuel to come out. I also checked it again when I got it back to the house in the driveway on even ground and did the same thing-- no fuel coming out.

When I checked the float levels earlier this week on a cold engine... it was set perfectly and just a little bit of rocking would cause fuel to drip out. It seems as though this might be the problem-- the float level is getting stuck when the engine is running. It aso seems like it has gotten worse over time. It started out doing it after driving it a relatively far distance and now I can't get a mile from the house before it starts to do it.

So I am not real comfortable with carbs and wondering if there is anyone that knows why the float level is sticking. I have read a little bit about the needle and seats getting gunk in it that would cause it to stick and that sometimes the bowl should be replaced as well. Any carb experts care to weigh in on my next move here?

Thanks!

Usually if you get something in the seat it causes the bowl to flood. You should see if the needle is actually sticking closed (should have good pressure if this was the case) or if you just are not getting fuel (no fuel pressure). I think you're not getting fuel. I would replace the fuel line between the tank and pump to eliminate the possibilty of an air leak there. Don't put the filter back in. If it still happens the problem is in the tank or in the pump.

I'd do as phil says and start at the pump. Move the filter to after the pump before the carb. It's easier for the pump to push the fuel through the filter than pull. If all else fails bypass the electric pump and go back to a mechanical pump.

I ran a filter before and after the pump when I discovered my tank was full of junk, the mechanical pump always seemed to pull the fuel okay. When I swapped my diesel in I wanted to run a similar setup but after doing a bit of reading found the correct setup was a screen before the pump & a filter after. So if you want to swap a screen in place of the filter to grab the bigger sized junk that should work well.

Ran the line with no filter for a brief time to see if it would improve flow and give me an increase in fuel pressure. It did not. I was also able to see prior to doing that the fuel coming into the clear filter from the tank, it was bubbling as it came in. Phil and I both agreed it sounded like an air leak in the sender line.

Spoke with TBP and they are going to have me drop the tank, send it in, do an air pressure check and see what that comes up as.

Just to make sure, the Carter P4070 is a low pressure, high volume pump right?

Thanks. Just making sure. Gas tank is being sent in for pressure check. Will let you know.

I'm picking up on this a little late. If your tank comes back testing OK you might check the fuel pump wiring just because you have voltage you may not have the current needed to drive the pump properly. You would need to check both your voltage supply and ground for resistance with your VOM. Hopefully its a bad pick up in the tank.
Good luck

"If I didn't have bad luck"... fill in the blanks. So I got out in the garage and did some work today. Pulled the carb and adjusted the float level on the bench. Re-installed the carb and went to start the rig. Wouldn't start-- kept cranking but no fire. All of a sudden, I don't hear the whine of the electric fuel pump. I checked the voltage to the pump when ON and it was reading just a shade under 12V -- so this to me seems as though I am getting the proper electrical connection. Can this be anything but a bad fuel pump? It is less than a couple of months old so I am sure JEGS would replace it but just want to make sure.

This could also be an indication as to why I am getting extremely sporatic and poor fuel pressure...

You can have faulty wiring. High resistance in the wiring will let you have voltage supply without having the current the pump needs to run properly. Try using a old school test light not one with a led butt one with a true light bulb and see if you get a bright light or a dim bulb.

Spoke with JEGS tech service this morning and they think that it sounds like the motor burned out on it. I am not sure how this happened so quickly other than it could have been running dry quite a bit. After talking with them about my scenario, they felt that a mechanical pump was the best route to go. The way the tank is designed, the pick up tube is ultimately at the bottom and then has to "defy gravity" buy pulling upwards about 3-4 inches before leaving the tank. The only logical place to mount the pump was on the frame and that is probably another 1-2 inches higher than the pickup line. All electrical pumps are meant to have the fuel gravity fed to the pump and then the pump pushes the fuel.

I gotta say that the customer service was very good once again with JEGS. Even though they suggested I bought a pump and mounted in a way that it really wouldn't work, they are exchanging it for the mechanical pump (http://www.jegs.com/i/JEGS+Performance+ ... 5/10002/-1). This pump still runs 5.7-8psi so I should still see plenty of fuel pressure. I am guessing that this is why I was seeing fuel struggling to stay in the line before the pump.

I am really hoping that this ultimately solves the great mystery!

What Jegs is telling you is technically correct. Mechanical pumps are better suckers, electric pumps are better pushers. But I'd be surprised if the Carter pump cant lift the fuel from that tank. Ive been running a cheaper electric pump mounted higher than your Carter for 2+ years with no problem.

Anyways I ran similar looking mechanical pumps branded by Edelbrock. They did pretty well.
Sent from my C771 using Tapatalk 2

My carter has worked well, no issues and mounted the same as yours, I know of others
That have them with no issues.

I know there were tons of people that had similar set-ups as mine that recommended the Carter. At this point, I'm just going to take the possibility out of the equation so I can get this dumb thing driveable. Eventually I'll go EFI and will switch stuff back out.

Another gold star for Mr. Viperwolf1! His good karma will hopefully put him into a heard of elk this weekend.

After replacing the fuel pump again with a new mechanical pump, we took OJ out for a test run. Same thing started happening again. So after we get back, we (Phil) noticed their was another filter at the fuel inlet fitting to the carb. It was full of junk. We removed the filter and didn't have any more issues.

Crossing my fingers, but I think this may have solved the great dilemma.

Thanks again Phil.

Sweet, that's great news!

That's the filter I took off mine and banged it on the workbench and all the crap came out. I really hope this fixes it. You' ll laugh but I just got a text from my brother in CA, his 1970 428cobra Jet Mach 1 just stalled on the Benicia Bridge at rush hour...he describes the exact symptoms as your early posts! Cursed are those of us with old iron! Peter

I remember changing that filter out on my 85 Bronco II in highschool. My truck was running like crap & the new filter cured it.