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Unread 09-03-2013, 07:35 PM   #1
Leeharvey92
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74 cj5 problem

I just bought my second jeep. A 74 cj5. I'm having a problem with starting it once its warm. When it's cold it fires up just fine but if I've driven it and turn it off, it doesn't want to start for several hours. I think that it's vapor lock but I'm not sure. Any suggestions on what the problem is or how to fix it?

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Unread 09-03-2013, 08:01 PM   #2
superj
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Which carb do you have? What makes you think its vapor lock?
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Unread 09-03-2013, 08:19 PM   #3
CSP
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Vapor lock shouldn't be an issue for several hours.
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Unread 09-03-2013, 09:01 PM   #4
Leeharvey92
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Thought that it was vapor lock because venting the gas line and pouring enough cold water on it solves the problem
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Unread 09-03-2013, 10:11 PM   #5
CSP
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Is the tank vented to the charcoal canister which would have been below the master cylinder between the firewall and inner fender?

If not, and you don't have a vented cap that may be your problem. The gas that leaves the tank to make it run has to be replaced by air or it creates a vacuum. If it's strong enough, the pump just quits pumping fuel.
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Unread 09-04-2013, 05:16 AM   #6
Leeharvey92
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It's vented, and I don't have the problem until I shut off the engine and then try to start it again. If it stays on it runs like a champ
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Unread 09-04-2013, 05:31 AM   #7
colojeepguy
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It may simply be a heat soak problem. Gas boils in the hot carb & floods the engine. When you try to start it hot, hold the gas pedal all the way to the floor, then crank & crank & crank. An insulated carb spacer can help this problem, also some brands of fuel seem to be more prone to boiling than others. Try switching gas stations.
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Unread 09-04-2013, 06:14 AM   #8
bkeese
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If you think it's vapor lock, is the fuel line steel? If so, insulate the fuel line and move it away from the exhaust manifold (heat source) and as colo said a spacer under the carb.

Check the compression, hot and cold. Maybe a tired engine with no enough compression to start when hot.
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Unread 09-05-2013, 05:10 PM   #9
Leeharvey92
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Thanks guys. Let you know if that works
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