Hard Time Starting After Warm Up.

Have you checked the timing and points?

People don't seem to understand anymore that engine diagnosis is hopeless unless they begin with establishing the basics in logical order.
Any tune-up must begin with bringing the basics into spec first.

 

Seems to run great after startup. Yeah sometimes it starts right up after shutdown, other times it does this.

I guess I need to get a timing light

Weird thing is it never did this until I switched to a modern starter

 

You can do it without a timing light and get it running well... just need to do it methodically.
-replace plugs
-check plug wire resistances (replace if off)
-check coil resistance (replace if off)
-replace/clean fuel filter
-remove any air filters
-check gap and angle of point contacts
-adjust valves
-(with engine warm and running) rotate distributor until the idle is as high as it will go, then back off a few degrees.
-set idle and mixture screws to the factory "starting point" and see where you are
-lean out mixture screw slowly until idle stops getting higher, then richen 1/8 turn or so (if this screw goes outside of its normal range in the manual, time to change jets)
-adjust idle screw until you're in the 600-700 rpm range
-put air filter back on
-go for a drive and check the plugs to get mixture dialed

I'm sure someone can correct me if I got something mixed up.

 

Or he can try this. Look Ma. No timing light! How to Time Your Motor Without a Timing Light | Old Jeep Carbs LLC

 

Hook up your vac gauge. Remove all vac hoses and plug the ports so there are no leaks. Start 'er up and let 'er idle to warmed-up. Observe the gauge. Use your distributor wrench to loosen the holddown bolt and advance the timing. Watching the gauge for the highest reading of the needle. Then back off the advance to drop that reading by one or two inches-of-mercury. Lock down the holddown bolt. Turn off the ignition switch. Wait two minutes. Start it up again. If the starter spins the motor good and fast, you are done. If your starter acts like the battery is dying, then loosen the holddown bolt, and back off the advance a smidge, snug the bolt and try to start again. When you get to the point where the starter switches from tired-old-dog to frisky-young-pup, you are at optimum. Lock it down, put all the air cleaners and vac lines back on. And close the hood.

 

Oh yeah, forgot. You can do the lean mix with the mixture screw, and set the idle speed screw to your 700 rpm. (mine idles smoother with the idle speed set at about 950 rpm, give or take a little). You should have more power and better gas mileage, afterwards.

 

Completely noob question.

Where should I tap vacuum for the gauge? If you look at my video, it looks like there is a port under the intake on the carb, facing the camera.. is that it? Should that be capped off normally?

 

Tap the port below the carb, on the side of the head.
Normally it is plumbed to the PCV, and vacuum pump and vacuum wipers, if any.

 

gotcha.. mine has a draft tube.. should still be there though, right?

 

If you really want to get your carb mixture adjustment set correctly, start the jeep and let it get to operating temp. Operate the gas pedal a couple of times to make sure all carb circuits are clear. Turn your idle speed adjustment screw down to where the engine is barely running. Then adjust your mixture screw for the highest idle speed. Once you have found this, turn the idle speed adjustment back to that recommended for your Jeep. Mine is 900, but with the alternator, carburetor and pertronix I have, I can easily idle it down to 700 and still have no issue. I settled for 800 rpm. I had issues with my Jeep starting, just the same as yours, once I put the Weber 2-barrel on it, but most the time I have found I don't need to use to the manual choke even when it is cold -- "cold" being a relative term out here in the psychotic state of CA. I have found if I just pump it once and hit the starter, it rolls right away. I was flooding it originally, especially when I would drive it, let it sit for 10-15 minutes and then try to re-start. Good luck on your troubleshooting...

 

Good news! I'm calling this one fixed. Took the carb apart for the 4th time. Cleaned it out good. Checked float , needle and seat.

Blew compressed air through the intake port of the fuel line, and a big chunck of black something flew out. Not sure what it was or where it came from.

Has been starting up fine, and running great after all that.

Thanks for all the help.


---Edit---

Nope, still doing it.

 

Well after battling this for a year... I finally figured out the issue...

Should have applied occam's razor..

I knew it had something to do with the starter being switched from the old foot pedal type to a keyed type...

With the foot pedal type I would turn the key to on, then work the starter.. would start right up.

But with the keyed type.. it would never start or try to start until after I released the key. That should have been a red flag!

The stupid ignition wire to the coil was in the ACC location on the key instead of the IGN pole.

I'm dumb, so much frustration over this year for a stupid oversight.



So gentelmen.. this is what it looks like when you have your coil wired to the ACC post on your key:




I need a beer.

 

Pete's First Rule of Mechanical Diagnosis… "What is the newest part?"

 

When switching from the footpedal starter to one that uses a solenoid, just hook up a push-button on the dash to operate the starter. But don't tell anyone so that it is harder for someone to boost your ride if they cannot figure out how to start it. This way you don't have to change out the ignition switch and key. Especially if you have JEEP stamped on the key and you want to keep that. To really confuse them, use your horn button as a start button!

 

Good place to hide a push button start switch would be behind the dash horizontally. Make a small bracket to hold the switch behind the dash so it can't be seen but so you can curl your upside down palm to press the button to start