Jeep Wont Start After Running For A While

Hoping you all can help guide me in the right place to get started. 72 CJ5 V8304.
My jeep barely starts if I drive for more than 15 minutes or so and have to park or shut the engine down and then restart. It will crank and barely turn over, sounding almost like the battery is low and after a few seconds it will turn over and barely start.

I have replaced the battery (now have Heavy duty), alternator, plugs, and battery cables.

I am reading that maybe I need to look into a high torque starter? Thoughts?

Thanks in advance!

 

You state that the jeep barely cranks after it has gotten hot., question#1 If allowed to cool off , will the engine crank and start normally again without anything else done to the vehicle, that would be a telling indicator

 

My thought would be that it apparently didn't need one for the first forty-five years. Something else is the root problem.

Solenoid, or cable connections, including grounds? Have you try bypassing or 'jumping' the solenoid/starter?

 

And how many starts are in a starter? 45 years worth? I think there is more than one thing going on here at the same time. Work on one at a time. Clear up what Pete suggests and let us know what you find.

 

Hard starting when hot can be related to too much advance. You can test this when it's hot by removing the coil wire and cranking the engine. If it hesitates when connected, and not when disconnected, it's the ignition of fuel that's slowing the cranking.

As Walt mentions, the starter may have an issue, and is weak against the more difficult hot-start condition. Starters have also been known to heat-soak, where the exhaust heat raises the winding resistance so much that the battery can't turn it when hot. Not sure I believe this, but it's one theory.

 

It may indeed need the starter serviced - although it seems to work okay when the engine is cold and harder to turn.

I'm just saying why leap to a "hi-torque" starter as a solution when the OEM worked fine until now.

 

A starter can get heat soaked, Old 300 6 cyl Fords were very good at cooking starters. At least mine were.

 

timing,then starter.

 

Yes, first and second start of the day is fine.
Carb isnt perfect, but its been sprayed clean and I replaced the hoses.

 

Yes, if I let it sit it starts right up.

 

Thanks- I replaced the starter about 3 years ago and only drive in the summer months.

 

Sorry for the delayed responses, my notifications were off for some reason. Thanks for the great suggestions. Looks like I should start with timing and the move to starter.

THanks, I'll give this a try!

 

cables and grounds I replaced along with the battery. It made a difference for sure, but still happens. Solenoid isnt that new so I'll try replacing that too, good thought.

 

Had the same issue on a 360. Adjusted timing and replaced everything except the starter. Only after replacing the starter with a powermaster hi torque didthe problem go away.

 

Voltage drops can be measured across the starting system. Heat=resistance. Resistance values =.2 volts per connection and .2 volts for the cable . So on a ford style you have .2 @the bat post .2v for cable and .2v for each solenoid connection and .2 volts for the starter connection. So a tight system has .8v max voltage drop for positive side. Measure voltage drop with voltmeter lowest scale while cranking with coil wire removed and grounded. Crank engine measure voltage drops from center of bat. Post to center of starter terminal. On ground side measure center neg post bat terminal to engine block cable bolt. Ground side max. .6v voltage drop observed while cranking. If you have old school multimeter low scale pos lead to block neg lead hooks to center of neg. Batt post. Charging systems can be tested same way except 10 amps current flow max.

 

I had the same issue wasn't an ignition problem on mine as I could have it start no problem if I push started or was able to roll down a hill. Starter was swapped out no issue since

 

Holy old thread Batman wonder if it ever got fixed....