hey I know its not a cherokee but I have a 1987 yj with a carburated 4.2L. Im having problems keeping it running. I changed the inline fuel filter up by the carburator and it seemed to stay running so i took it for a ride for about 20 min and it started to buck and sputtered out on me. It has an inline electric fuel pump that is definantly not factory. I dont know a whole lot about carbs but I took it apart and inspected the float bowl. It seems to be filling the bowl alright and the floats seem to be all right. I also inspected the needle and seat and they are very clean and not gunked up. However when I turn the key to the on position so the fuel pump kicks on it seems to be pulsing more through the return line. I tried pinching it off a little with a hose clamp and turned up the idle a little and it seemed to run better. I drove it for another 10-15 mins. and then let it idle for a while and it died. after it died the fuel pump wouldnt kick on, so I let it sit for a while and it worked again. Im wondering if it may have a vapor lock problem but im not to familiar with vapor lock or carbs. Any suggestions would help and are much appreciated. Thanks

 

With the electric pump always on,(I'm no expert) but I would suspect flooding if you don't have a return line.

 

So I did some research on vapor lock and it made me realize something. Whoever owned this thing before me zip tied the fuel feed line to the coolant hose. First do these carburated 4.2L have a lot of vapor lock issues? And do you think that moving this fuel line to a cooler spot will help?

 

If the fuel line is against the coolant hose I would say you have a fine opportunity for vapor lock. Might have a problem with too much fuel pressure over powering the needle and seat.
clint

 

does any one know if the 87 wranglers came from the factory with an electric fuel pump or a mechanical? I called the parts store and they told me it was supposed to have a mechanical pump. I looked over the engine and could not find a mechanical pump or mechanical pump block off plate. Any input helps. thanks

 

Somewhere down the line the float bowl is running dry and not refilling which sounds to me like a fuel pump issue. It does have a return line I just restricted it a little not all the way. So flooding is out of the question. But if i let is sit for a while it will start right up and run for like 15-20 mins. Im confused please help. also I rerouted the fuel line away from the coolant hose.

 

This is a classic situation of not getting enough fuel. If you were vapor locking the electric fuel pump would compensate for that by pumping the vapor through until the fuel bowl is full. If the line was against the exhaust pipe then that would be another matter. So you have to figure out why you have not gotten enough gas to the carb. There are two possibilities. One is the filter in the tank is plugged. The other and more likely is the fuel pump is worn out. I replaced one the other day on a project vehicle. Take the line loose from the carb and put your finger over it while it is pumping. It should have about 5-8 pounds of pressure and pump a steady stream. If it doesn't, work backwards.