It's an 84, 302, 4 speed, and it's driving me INSANE!

Starts perfectly first thing in the morning. One pump, turn key, it's started in about 2 seconds. Once it warms up and for the rest of the day, it's either excessive cranking or the motor sounds like it is struggling (slow cranking, similar to a dying battery). Sometimes it'll start, other times it will have to sit longer to "cool off" a little.

The battery is new, but my immediate thought is timing. I've advanced it a little bit (I assume advance results in an RPM increase?), a few degrees, but it didn't seem to affect anything.

So I'm at a loss- cold start perfect, but once it warms up, it struggles to start every time.

 

Advanced timing can result in kickback especially when warm. Hot temps cause more start trouble than cold weather. Headers in particular, install heat shield if necessary.

Make sure starter cables are of sufficient diameter or gauge and all connections are clean and tight. Test for voltage drop on each cable and connection.

 

That all makes sense but what would account for the cold starts being perfect and hot starts being tough. I have factory manifolds on the truck so I'm not certain its heat affecting the start. I mean it can sit for 3 hours and cool off to what I think is enough but any start after that initial cold start is not an easy one.

 

...the heat.

 

Carburator or fuel injection?

If it's carbed your choke might be sticking shut. That would make for a hard, rich hot restart. Also might look for fuel leaking inside the carb down into the motor flooding you out.

 

Yes, it could be more than one issue. Excessive cranking, without engine firing up, points to "flooding" or something like that.

"Slow cranking" as described like a dead battery when warm/hot points to a heat soaked starter, bad/corroded cables, etc.

 

Retard the timing, slightly, and see if the situation gets better.

 

Yeah I realize that was a real stupid question after I posted it haha. Makes sense. I replaced the starter cable but it's 6 Gauge. Maybe it's too small And I should make it 4 Gauge.

 

Would a flooding carb be the result of a needle valve sticking open? I rebuilt the carb but maybe a piece of dirt made it into the needle/seat assembly

 

I thought it might be the choke. What I did was before I started it, took the air cleaner off and the choke plate was open about 90%. I could open it more by hand but it seemed a minuscule amount. I also tried disconnecting the choke but all that resulted in was a very high idle while driving.

 

Perform voltage drop testing (look it up, trust me) at each cable and connection both cold and hot.

 

Ok, I'm gonna start there. Something tells me the cable is too small. Maybe the starter requires a little more current (or drawing more voltage) when it's hot and the cable can't handle it.

 

Worn bushings in the starter will also cause a "hot start" problem.

 

I know this doesn't mean a thing as new parts can certainly be defective but it is a new (remanufactured) starter. Hoping that's not the problem.

 

I just found that the throttle linkage is sticking open slightly and that there is no throttle return spring!! I'll be installing one. Maybe because it's staying open a little it's allowing too much gas in under starting conditions?