Now what?!!!

[lowesguy]

So my old 78 truck started really weird yesterday at work,like running on 7 cylinders? took back roads home just in case it stalled out,restarted today runs fine,lifted the air cleaner and inspected the carb,noticed fuel pooling on top of the accelerator pump location,manually flicked the throttle with engine off,accelerator pump sounds crunchy? think thats the problem with strange running condition yesterday? whats your thoughts on this problem,I was thinking carb rebuild kit,truck is stock and has run great for 20 years!

[Ziegelsteinfaust]

I had a similar issue with my carb where one day it was awesome mpg then the next in the tank. Smooth running then the next had tons of flat spots.

Just to be sure verify that your distributor is pulling the full timing you set it at, and that vacuum advance kicks in.

[lowesguy]

Well haven't done much to the engine in 10 years! it just has always been so good,but I did the dist cap,wires,and replaced the carb with a brand new one 20 years ago! these trucks last a long time,forgot I did the heads 20 years ago also. will drive it tomorrow and see if the problem comes back,don't think timing or ignition is bad,because it runs great today? only thing I found was the fuel pooling and crunchy sounding accelerator pump on top of carb. plugs have been changed recently,passed emissions with flying colors Dec.

[mud.man.rj]

Sounds like the float is stuck that is why fuel is coming out the accel pump.

[mgchevyparts]

Dirt in the fuel will cause needle/seat to stick open causing flooding issue. Can come and go depending how much dirt. Sometimes you get lucky and it goes away and doesn't happen again.

[lowesguy]

Yea but what got my attention on the visual inspection was the pooled gas above the accelerator pump and sound its making,I believe I have a Rochester QUADRAJET 4 Barrel Carburetor,the cup seal in the pump goes bad and can cause my condition,fuel leaking up the shaft and ends up topside,luckily I can pull the carb and just take the top off for replacement,and its cheap!

[INSIDIOUS '86]

Awww why you still messin with them old things? Lol
Posted via Mobile Device

[geezer#99]

When you get dirt stuck in the needle/seat and the carb floods then one of the common places fuel goes is out around the acc pump shaft. If you hear it making a noise when you push it down and fuel squirts into the primaries then it's working right.
Whatever was in the needle/seat might have flushed out by now.
If it runs bad again then suspect it's flooding. Then you'll need to tear into it.

[lowesguy]

I'll check that today,rebuild kit is only $29,maybe it was dirt or something else?

[mud.man.rj]

When the accel seal leaks it just doesn't pump, fuel only comes up past it when you have a needle/seat/float problem.

[lowesguy]

Thanks for the input guys! really helps,I've been working on fuel injected cars so long started to forget how the carb works!haha,will dirve it to work Sun see what happens,started it today,seems fine.,

[jjzepplin]

Originally Posted by mud.man.rj

When the accel seal leaks it just doesn't pump, fuel only comes up past it when you have a needle/seat/float problem.

This. Make sure your rebuild kit has a "blue" acc. pump seal. The black one gets damaged by the ethanol. I rebuilt my carb and it lasted one year. Put a blue pump seal in there and it's good again.

[lowesguy]

Just came back from a drive and runs great! must have been some dirt somewhere?

[geezer#99]

Now you've been forewarned. Time to check or replace the fuel filter before it happens again.

[mud.man.rj]

I would change the filter and run some fuel system cleaner thru it too.

[jjzepplin]

Originally Posted by geezer#99

Now you've been forewarned. Time to check or replace the fuel filter before it happens again.

Pops lives there. And sis.