• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Carb problem *Updated after different carb*

J

Jcode68

Member
So we redid my '68 and took it out for the first highway drive back to my house from my uncle's shop. It was idling kinda rough and had trouble running when in gear. We adjusted the idle up some and that helped a little. It's idling now at around 1100 in park and around 900 in gear. The motor is a 347 stroker with an auto tranny BTW. So I drove it about 12 miles on the highway and turned on to the backroad to go home. I kicked it in the butt and it totally lost power, almost completely died even. I let off the gas and it came out of it. Tried it again with the same result. Well I slowly got it back up to highway speed until I had to stop at the stop sign. Once I got to the stop sign, the car died and would not restart. We waited a couple minutes and it finally popped over but sputtered like it was flooded and died. We got it to the side of the road and waited for a few more minutes. Finally got it started, but it really acted like it was flooded. Got to my house and it was having a hard time staying running when in gear. I tried starting it about an hour later, and it started, but it didn't "pop off" like a new engine should. What the heck is wrong? The motor was tested when it was built and ran fine. I was driving it around town without any problems. Edelbrock said to check fuel pressure to make sure it's not too high, otherwise send the carb in. There are no noticeable vacuum leaks. The only thing we did to the engine was take the carb off to put the engine in and put it back on. The carb is a Edelbrock thunder series 650 with electric choke.
Thanks, Justin
 
Re: Carb problem

Sounds like it could be getting too little fuel also. Have you checked the fuel line going into the carb? Disconnect it and run the hose into a can. Crank the car and check the fuel.
 
Re: Carb problem

when you say over fueling is fuel coming out the exhaust, check the venturi also when you floor it to see fuel being shot into the carb if it isnt a good strong stream then id be adjusting the air/fuel mixture. the other thing it sounds like a timing issue id check the base timing. Check plugs and leads, dizzy etc for anything that could cause the spark to be earthing out possibly then go from there
 
We tried a new carb today, a Holley 750 double pumper. It ran better right away but we had the same problem after driving on the highway. It shut off, didn't even pop. We waited about 10 minutes and it started and ran enough to get home. No vaccuum leaks. Carb helped but didn't sure the real problem. We were thinking vapor lock or bad coil. Everything was brand new on the engine and it was timed by a professional. In ran ok and idled ok in town for almost an hour. So it has to have something to do with driving it on the highway and then slowing for a stop. Before it died on the stop sign, I kicked it in the butt and it cut out just like the first time. Drove for a couple more miles and died at the stop sign. Not sure what to do. It's like going to the doctor when you feel bad and you feel fine when at the doctor, go home and :puke
 
Sounds like as mentioned above, maybe a fuel line getting blocked or the pickup in the tank getting plugged. You need to check fuel flow at the carb once it dies on the road, not back at the house.
 
We didn't think about it at the time, too discouraged I guess. Nothing looks like it's wrong when it's home. Fuel pressure has been steady at 6.5 otherwise. The first time it quit, we checked and the carb had fuel to it. We didn't have a pressure guage hooked up at that time. I guess I'll just have to take it out and drive it until it shuts off. We can check fuel pressure and see if spark is making it out of the coil.
 
New gas tank? If not there could be all kinds of crud blocking the pickup. What about the fuel filter?
 
I had this same problem and it was a blockage in the line that was getting "pulled up" at throttle. It never made it through the line. Disconnect your fuel line before the pump and make sure you can draw fuel through the lines. You can also disconnect the line at the pump and tank and blow air through the line. Connect it back at the pump and disconnect it at the carb and run it into a container. Crank the car and see if you have fuel flowing out. You should get a lot of fuel going into the container. If it's not pumping equivalent to your pump rating you have a blockage or pump issue. To eliminate the pump run a line from a gas can to your pump and try the same thing. It could be in the tank at the pickup also. You first need to make sure you are getting adequate fuel and if not, find the blockage.
 
Fuel pressure has been steady at 6.5
Click to expand...


If I remember correctly..... Edelbrock recommends a maximum fuel pressure of 4.75 PSI. With the replacement Holley, have you by any chance adjusted the floats?
 
"daveSanborn" said:
If I remember correctly..... Edelbrock recommends a maximum fuel pressure of 4.75 PSI. With the replacement Holley, have you by any chance adjusted the floats?
Click to expand...

When I called Edelbrock originally, they said optimal was 6.5. I haven't done anything to the Holley. We may have found the underlying problem though. The carb was part of the issue, and the rest of the fuel system seems ok. But t still quit on me. I bought a new coil and today we drove it until it died and changed the coil while on the road. The car started right up. It idled even better and didn't quit on me when we took it for another run. Now to adjust the built in rev limiter in the pertronix...
 
You must log in or register to reply here.
Back
Top