Engine Troubleshooting

[ajgriffin]

So I'm having some trouble with the truck. Whenever I put it in gear it idles down really low, stays running, but idles low. Then when I go to accelerate it shuts off. The only way I can keep it running is if I get it some gas before I put it in gear. My choke doesn't work so the clutch plate is always open, but I don't know if that has anything to do with it.

Any suggestions?

[highperf4x4]

There's alot of possibilities. Could be a bad vacum leak and a weak accelerator pump to go along with it. Sounds to me like the timing might be too slow and the idle screw set too high. What carb/distributor are you running and what type of choke does it have? Also, have you tried adjusting the idle jets?

Another thing to consider is the condition of the engine. Have you done a compression test on it?

[ajgriffin]

Originally Posted by highperf4x4

There's alot of possibilities. Could be a bad vacum leak and a weak accelerator pump to go along with it. Sounds to me like the timing might be too slow and the idle screw set too high. What carb/distributor are you running and what type of choke does it have? Also, have you tried adjusting the idle jets?

Another thing to consider is the condition of the engine. Have you done a compression test on it?

I have the timing set at 8* before TDC if I remember straight. I'm not sure how I would know if my idle screw was set too high -- I don't have a tach on the truck. I don't know anything about the distributor but the carb is a Holley 4160 with an electric choke.

I haven't messed with the idle jets or done a compression test. I don't know how to do either of those.

[68C15]

why is that vacuum port on the pass. rear of the carb open? that will do it. it should go to the PCV valve.
do I see a brake booster with no vacuum hose running to it? IIRC there should be another 3/8" port on the front of the carb. if so, run that to the brake booster.

what's the number on the front of the choke horn? 80457S?
the idle mix screws (idle jets) are on each side of the front metering block. ideal setting is 1 1/2 turns out from lightly seated. a good carb guy could do a full tune on it for you.

[cdowns]

you might want to change the rubber fuel line to a metal fuel line before the fire

[highperf4x4]

Originally Posted by 68C15

why is that vacuum port on the pass. rear of the carb open? that will do it. it should go to the PCV valve.
do I see a brake booster with no vacuum hose running to it? IIRC there should be another 3/8" port on the front of the carb. if so, run that to the brake booster.

what's the number on the front of the choke horn? 80457S?
the idle mix screws (idle jets) are on each side of the front metering block. ideal setting is 1 1/2 turns out from lightly seated. a good carb guy could do a full tune on it for you.

This pretty much covers what I would suggest looking at. I can see the vacum hose for the pcv valve laying on the valve cover. That needs to be hooked back up to the carb. That may solve the problem.