Starting issues

[asappin]

1969 Bronco, 302 V8, electronic ignition, Holley 2 barrel carb

When I go to start the bronco it seems to be sluggish on firing. It will turn a few times then finally will start and sputter then smooth out. If I turn it off after it runs for a few minutes and crank again it fires right up and is smooth right away.

Any ideas on what might be causing the sluggish crank? It’s not battery related and I have a newer mini starter that was put in a few years back.

Thanks in advance

 

[Oldtimer]

Is it cranking slower, or just cranking longer, till it fires?
The gas may be evaporating from carb bowl, and you need to crank till pump has filled up carb.

 

[73azbronco]

old motor?

 

[asappin]

It is just cranking longer and when it does fire it stumbles for a little bit then finally smooths out and runs good.

Motor was rebuilt about 12 years ago prior to me owning it. Compression test done on the engine and it has good compression across all cylinders

 

[DirtDonk]

Check the workings of your choke. Is it manual, automatic, or full electric?
Since you still have a carburetor they don’t stay adjusted forever. You have to tweak them often. Sometimes constantly!
Which electronic ignition?
Have you checked for vacuum leaks?

 

[asappin]

It has a manual choke. It has a Pertronix electronic ignition and coil.

It seems like it’s flooding while it’s sitting overnight and once it burns all the fuel off it runs great but when it turns over and over it floods it.

I have not checked for vacuum leaks

 

[asappin]

Here is a video showing it running with the accelerator pressed but dies when I let off

I turned the key off and fuel is dumping into the carb

I would assume that fuel shouldn’t be dumping into the carb after I turn it off but I’m no expert by any means

 

[DirtDonk]

In the first video, doesn’t look like your choke is closed at all. You say it’s manual? How far do you pull the knob when you start it cold?
And when you’re pulling the knob initially, are you pushing on the throttle slightly to release the locks?

I might have to try on a bigger screen, but I can’t see any detail in the second video. However, and answer your question, no. Fuel should never dump in the carburetor after you turn off the engine.
Lots of things can be at work here. All typical of a carburetor. And even more typical of a carburetor on modern fuels.
One could be a needle and seat that’s slightly stuck open. Another is a float level set too high or too low. Another is too much fuel pressure from the pump.
All of which are very common occurrences. There are probably other reasons for fuel to dribble out, but I’m not sure what they might be.
Others with more expertise and carburetors may know.

 

[Reservationcody]

It has a manual choke. It has a Pertronix electronic ignition and coil.

It seems like it’s flooding while it’s sitting overnight and once it burns all the fuel off it runs great but when it turns over and over it floods it.

I have not checked for vacuum leaks

You’re getting fuel into the carb while it’s sits overnight? If so is the gas tank vented properly? We had a British car flood a carb cause the gas tank could not vent and pushed gas back through the carb.

 

[EPB72]

Yeah there is nothing good about your videos, too much fuel is going into the carb ,, being a fuel pressure problem or a carb problem ?? most likly the later but confirming fuel pressure would be nice . look up needle and seat replacment on a center hung float holley , it can be removed and replaced with out removing carb,, also note with all that fuel running into engine after shut off i'd bet your oil is fuel saturated ,, correct flooding and change oil

 

[DirtDonk]

And at the very least, make sure your PCV valve is functioning properly to help remove residual vapors from the crank case.

 

[DirtDonk]

I wonder if that is also why it doesn’t run right initially? If there’s fuel getting into the crank case, you could be running ultra rich for the first few moments because gas vapor is being sucked in through the PCV system. Doing its job.