Hard Starting when hot

[Schmed]

I have an 83 CJ-7 with a 401 V8. When I drive it and then shut it down right away and the temp climbs to ~220 or 230 because the fan is no longer turning, it becomes almost impossible to start. I'll turn the key, and the engine will hardly turn over. I have to let it cool down to ~150 before I can get going again. It makes the same kind of sound you'd hear if the battery was dead, and I was trying to start it. The bat. gauge reads 12 v though.

Is this a choke problem with the butterfly valve occasionally staying in the closed position? It also runs rough in the morning until it's heated up fully. It'll lose power when I try to accelerate. Once it hits running temp though, it's fine.

I really appreciate any advice you might have. Thanks
Joe

 

[Bounty__Hunter]

Sounds like maybe the starter is getting too hot. It may need replacing or a heat shield installed. Is it slow to crank?

 

[Schmed]

Slow to crank? It cranks slowly when hot. It'll turn the engine over slowly 3 or 4 times but won't start it. It's fine when cold. Is that what you mean?

 

[Bounty__Hunter]

Yes. Sounds like your starter may be worn out and is easily affected by the heat. A new one may be fine at the hotter temps. I haven't heard of the AMC engines needing heat shields on the starters as the GM V8's do.

I'd start with the starter since that determines your crank speed (among other things, but I don't think the heat is affecting your battery).

 

[Schmed]

Thanks for the tip. I'll take a look at the starter. Anyone else have any ideas or agree/disagree with the starter idear?

Thanks again
Joe

 

[jeepin916]

nope good idea

 

[TwistedCU]

Sounds like a bad starter to me, too. As for the cold engine perfoming poorly, well I always get my old YJ good and warm before getting into it. Just not healthy for a cold/cool motor. When it gets to the right operating temp, the pistons, rings, valves, and everything else has expanded to where they're comfortable. My old auto shop teacher used to say "warm it up, run it hard, cool it down." I've found it to be good advice, especially with an older engine :wink:

 

[jaber]

lug nut

I've got a couple of the big-blocks, mostly 360s and its common in all that i have running to be slow to turn-over after the temp goes up. I agree that if it wont turn the motor enough to start then a new starter is in order. With Splitfire plugs in mine it only turns about two turns and its running, even hot. Just my $.02.

 

[Schmed]

Cool, thanks fellas. I went and replaced my starter yesterday. Had to drop the headers to get to it. When I finished and reconnected the battery, the alarm scrambled itself and killed my ignition. Now I gotta tow it in to Circuit City and have them fix my alarm. Go figure. Everynow and then I wish I had a car with a nice warranty with leather seats that was quiet and gets good mileage. Thanks again.

 

[Utah_jeepster]

hey tug

Bounty hunter hit it right on the spot.
Electricity flows better when its cold. The starter engages when the motor is cold and you didnt mention that is was ever slow to turn over when it was cold so the battery has the amps nessasry to turn the starter over.
When the starter motor is warm thou it doesnt.
Replace the starter and for giggles have the battery tested as well for cold cranking amps. Pep-boys or any auto store will be happy to test it for you with evil thoughts of hoping to sell you one...lol. Your there buying a new starter any way.