fuel pump - starting questions...

Could I add an electric fuel pump to my 85 CJ 7? If so, what model and where do I put it. I have a hard time starting this thing after it sits overnight. I'm thinking the gas is flowing out of the carb somehow. I have a weber carb. I have to pump the gas and crank for 30-45 seconds, sometimes up to 2 minutes before it cranks. When it does crank it ususlly starts with a LOUD backfire. Could it be something else?

Reply to
HomeBrewer
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Sounds like your gas filter is in upside down.

The filter has two outlets. The center one goes to the carb and the 'top' one goes to the return line. If the return line isn't at the top, gas will syphon back to the tank when it sits air locking it.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

HomeBrewer wrote:

Reply to
Mike Romain

Just what I was thinking, Mike. Changing over to an electric fuel pump seems like an awfully round-about way to correct a simple problem, kinda like welding up all-steel tires because one of the rubber ones has a slow leak. But, hey, it isn't my Jeep.

Reply to
Lee Ayrton

Reply to
Steve G

Hmm, choke - I'll check. It's electric and I wasn't sure where to hook it up. Can it be hooked to a switched 12v that's constant? Or does it need to close when up to temp?

Reply to
HomeBrewer

You have no freaking choke!!????

What the heck do you think a choke is for anyway?

Hint: Cold starts....

If the choke isn't hooked to power and the vehicle is running, you have no choke. I mean that literally.

If it had the guts for a choke in it, the choke plate would be closed with no power to it and the engine would not run.

Someone has gutted it or it has broken.

The power for the choke comes through the oil pressure safety switch so the choke only sees 12 volts when the engine is running. Having a key switched 12 volts won't work, the choke will fast burn out.

The power wire is a plug with 2 red wires going to it.

You also have a heating element under the carb for cold starts. This gets power through the same switch, but has a relay on it for a direct

12 volt feed. The oil switch is only for the relay trigger.

I would highly recommend you go get a Haynes manual for the CJ's. It has great wiring schematics.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

HomeBrewer wrote:

Reply to
Mike Romain

If his choke was not hooked up then it would not have a problem with cold starts as it is supposed to be closed when cold. It may well be a problem once it warms up and doesn't open like it should but it's not likely to be a cause of his jeep not starting.

Not having seen the vehicle, my money is on the choke not closing properly. If it is stuck open then this would indeed be a cause of it not starting and also backfiring when cold.

If that's not it, then I think the immediate problem lies in the fuel delivery system ie: Pinholes in the fuel line, leak in his carburetor float bowl or leaking diaphragm in the fuel pump. Most likely a combination of the first two. An easy test would be to prime the carb with a little gas before trying a cold start. If it starts right up where it would normally sit and crank then you have fuel starvation issue. You should have to wedge the choke open with a screwdriver before you can pour a little gas into the carb.

You can hook up the choke power to any switched 12v line and its not likely to burn out any earlier. The only problem I can see coming from this is you'll have a higher power drain on your battery and your choke will act as if the engine is running and open prematurely. If you're not the type of person who likes to sit for long periods of time with the ignition on and your engine not running this should not be a problem for you.

Reply to
Jumpin' Jiminy

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