Alright. Now think about what you wrote.
would only run if it was taking on a lot of fuel,
. Engines run on a mixture of fuel and air that is ignited by a spark to create an explosion. Too little fuel, or too much air, and the engine won't run well at all. You statement is screaming "vacuum leak". There's air getting into the fuel system somewhere that's screwing up the fuel/air ratio causing the engine to run bad.
Now, think about the sequence of events. You sent the truck to a mechanic to work on the brakes. That has nothing to do with the fuel system. However, if he was working in the engine compartment, he could have easily caused a vacuum line to slip off and cause your problem.
When you got to Denver, you got snookered by mechanics who either don't know what they're doing or are deliberately cheating you. You stated
new points, new condenser, new plugs, new wires, new rotor cap
, yet they replaced the points, coil, and spark plugs. They were already new. How would changing them fix anything?
Next, you state that the spark plugs are covered with black soot. This is an indication of too rich of a fuel/air mixture, which is the exact opposite of a vacuum leak.
Nothing irks me more than people replacing brand new parts simply because they don't understand how to troubleshoot. You don't need another coil, points, or anything else, although you
may have to replace the plugs depending upon how badly they were fouled.
Based on your symptoms, you may have a combination of problems, but they are all fuel/air related. There's nothing wrong with your ignition system (coil, condenser, plugs, wires, distributor.)
Here's what you need to do.
- Look for vacuum leaks while the engine is running (you do this by spraying carb cleaner around every vacuum nipple, at the base of the carb where it mounts to the manifold, and anywhere else that air can get into the engine other than the air horn of the carb, where it's supposed to come in. If the engine speeds up, you've found a leak. Do not stop looking if you've found one. There may be more.
- Look at the spark plugs. Are they wet? You have unburned fuel. Are they covered in black charcoal (dry)? You're running too rich. They should be a light chalky brown after many miles of service.
- Look at the choke plate. Is it closed almost all the way? What happens when you open it with your finger? Does the idle smooth out? How about if you push it closed? Does the idle smooth out? Adjust the choke. Make sure the choke mechanism moves freely throughout the length of its travel and is not hanging up at any position.
- Check every rubber hose that feeds vacuum to something (like the advance on the distributor) for cracks by spraying it with carb spray. If the engine speeds up, you've found a leak. Replace the hose.
If none of that helps, replace the plugs, do nothing else, and see if that solves the problem. If it does, yet it reoccurs, go back to the list until you find the problem.
Whatever you do, do NOT replace or rebuild the carb. It's brand new. If you find a vacuum leak at the base of the carb, take if off and inspect the gasket. Place if over the manifold opening. Does it cover the intake holes at all? Does it sit flush with the manifold mount? Next, place it on the base of the carb. Does it restrict the area where the fuel dumps into the manifold? Is it missing a hole that allows fuel to enter through the accelerator pump? Does it sit flat against the base of the carb sealing it?
All of these things could be issues. Once you have verified something, you do not need to verify it again. One of the biggest things that drive people nuts is going over the same ground over and over again. Do each check carefully and then, once you've verified that it's not causing the problem, do not revisit it. The problem is elsewhere. Persistence is your friend.
If, after all this, you still have problems, come back and describe
precisely what the symptoms are at idle
and at speed. Does it just run rough? Does it stall at idle? When you step on the gas, does it bog down? Does it shudder? Does it die? Be precise. It matters.
