I have a 85 cj7 with a 258 straight 6 and recently when I have been refilling the gas tank she won’t start right away and I end up waiting 1 to 2 hours before she will start up and then she drives fine until you have to put more gas and the cycle happens all over again. Any idea of what the problem could be?
Could be fuel pump going out.
By far, the greatest source of grief on that model Jeep has been the feedback carburetor. Although I cannot piece together what happens when you fill up the tank to cause a no start it is likely that the Carter BBD carburetor is part of the problem. If your local mechanic condemns the carburetor I would strongly suggest using the 1979 pre-feedback model.
With warm weather here maybe this problem is due to vapor lock caused by gasoline boiling in the carburetor float bowl. After shutting off an engine that is at operating temperature there is a very brief spell of what could be called heat surge and that is what causes the boil off.
Asian cars of this era used carburetors which had sight glasses on the side of the float bowls and during spells of vapor lock the gasoline can be seen boiling after engine shutoff.
Excellent, @ok4450. If the OP lives in the southwest vapor lock after sitting still with a hot engine is a good possibility. If the hood is opened while filling the tank and the engine starts you might have saved the OP a lot of money and grief.
Thanks for all the feedback. I’ll run them by my mechanic friend.
So my carb is a webber and its not a vapor lock. Any other ideas?
The Webber carburetor installation may have crossed up some evap system hoses. You might stop pumping after a few gallons and attempt to start the engine and post the results. From here we are unable to know if the problem is too much fuel or not enough.