All right, first off to clarify, I realize I can search the forums but that option never quite yields to my situation.

About a week ago I noticed that whenever my truck is hot and I go to restart, it seems to act flooded and I need my foot to the floor and about 30 seconds of cranking for it to fire over, after wards it ran fine
Fast forward to this morning, I'm heading into work and I notice that in 3rd gear I have a random backfire through the carb, it happens accelerating and at cruise speed and it's got more and more prevailant as I went on my journey home. Get home and idle the truck and the idle jumps around between 400 and 800.

So assuming this is a points or a distributor issue, please talk to me like I'm 4. I can wrench well on anything but ignition, which I'm totally new to.
NOTE: the stumbling issue just started today after the truck sat for the weekend, and yes the distributor and points are old but I do not wish to dump money at the moment as its a little tight

 

One thing to look at with higher mileage engines, is the timing set will jump teeth because the chain starts to stretch excessively. Makes the valvetrain out of time.

Check for excess slop (by removing distributor cap) in the rotor as you move the crank to and fro with a breaker bar and socket. Remove plugs for ease of turning over. Basically the rotor should turn about as soon as the crank shaft. If not, that lends itself to the problem of worn timing set.

If everything is OK you can try cleaning and resetting the points. Also look to ensure that the condenser installed is known good. They are mostly junk today, buying a new one is not necessarily part of the process of elimination, sadly. If you have some freeze spray you could try hosing down the condenser and see if the symptoms go away. Ignition coils can also go intermittent or be affected only when hot. It's tough to catch this because they will test OK or close enough, for ohms resistance in primary and secondary.

Check for hot, bluish-white fat spark at plugs that snap in the air. Yellow or reddish, weak spark will not be able to ignite fuel reliably under compression in combustion chamber.

 

The engine was rebuilt recently by the PO so I'm assuming it's got new timing chain and gears. Couldn't a bad distributor cause it to jump timing also?

 

see edited post above

Yes, if the distributor has real problems, but it would be a constant thing, not only when warmed up or hot.

The PO says he rebuilt it? Did he provide receipts.... Can't really believe anything anybody says. Not very often anyway.

 

I will check spark in the morning. And no receipts but the PO is my grandfather who is a mechanic and has owned this truck since brand new, but since he's 300 miles away for surgery, I don't dare bother him.

Any other issues that are common that could cause this? I don't want to spam the thread and that way I can do multiple tests at once

 

Ah, gotcha. Well OK.

Backfiring through the carburetor is pretty much always a timing issue of some kind. Crossed plug wires could do it, or a bad valve. But these issues tend to be a constant.

The fact that it is backfiring through carb is key, and means ignition, and since it seems to be a "heat related" problem this further indicates a likely coil or condenser problem. (of course I could be wrong)

Possibly check for a broken roll or spring pin that secures distributor gear to distributor shaft too.

 

I'm leaning towards my coil being bad. I had issues of it grounding out through the bad tach I bought, so I'm thinking that sped up the death of it. Hoping thats the issue as when it comes to a distributor, well I know nothing

 

And when it finally starts in this condition, does it blow a cloud of black out the exhaust? If not, then it wasn't flooded. And if it's not flooded, and adding in the backfiring through the carb issue, would make me wonder about a fuel delivery problem.

I gained much unwanted experience about mixture lean-out causing backfires through the carb back on early 1970s Chevy small blocks.

 

I know it isn't flooded, just wanted to give an idea of what was going on. I'll take a look, I had adjusted my idle F/A mixture 3 days ago, ran them in till the engine ran rough and backed it out 1/2 turn, but this shouldn't be an issue?

 

OK.
I'm not saying it has to be, but I would not rule out a fuel delivery problem.
On a hot shut-down, gas can be boiled out of the carb's bowl. When you crank it, the bowl needs to be at least partially filled pronto, or else no start until enough fuel gets there without bubbles to cover the jet inlets. And fuel pumps work the worst down at cranking speed. So things like a dirty fuel filter, fuel pump with tired check valves, some air pickup on suction side of pump due to hose or line, crud on fuel pickup "sock" in tank, etc. can cause a fuel delivery problem.
My experience with fuel delivery problems is that they worse over time.

 

This sounds like two different questions. When you're trying to isolate problems you have to make sure you aren't making too many changes at once, otherwise the changes start affecting each other and then it gets frustrating if the problem still exists.

If it is truly flooding when it's off you either have internal leakage inside the carb such as the fuel level being too high in the bowl, or the fuel is getting so hot it's boiling inside and spilling into the motor - usually this occurs if a fuel line is too close to the exhaust somewhere.

If you think there is a distributor/firing issue and you still have the original points setup, you need to inspect the inner distributor parts. The vacuum advance will turn the entire plate the points mount to back and forth in it's normal operation. This plate has bushings it pivots on and if the bushings are worn or loose the slop will make your points gap vary so much that the misfires occur.

I will say a set of points and condenser are relatively cheap, so while I understand not wasting money I also don't think throwing some new ignition parts in is too out of line. On the flip side of that though is if you're really bucks down any shadetree mechanic worth his salt has filed or sanded a set of points to either get by until he could throw a new set in or decide if the project ran well enough to be worthwhile, so if that's where you're at you really just want the contact area of the points to be clean, parallel and as flat as possible.

 

This is what I'm looking at for the points with ignition ofg

 

Those are points, yes

 

That's I know, but whether they look good or not and the gapping is right, I don't know

UPDATE: the truck now stalls when left idling and no throttle given, I can hear a little pulsating of pressurized air around the engine bay on passenger side but it seems to be more manifold leak as it doesn't sound near the carb

 

Flooding is not my issue, after idling (and engine hot) checked the bowl and the fuel was up to about 3/4 and float wasn't sunk. So I'm thinking it's a coil. Primary resistance is 4.6 ohms and secondary is 8k (I believe)