Carb backfire

[jdsimon]

I have a 59 f100 223 inline. It will start normally but when I give it gas it backfires fuel and dies. I've read up on some similar posts and have gotten some ideas but these were all from newer models. It seems the difference that I have is that it starts fine and idles beautifully but won't take the load. New fuel pump, new carb.

[markguiver]

Sounds like the symptoms of a vacuum leak. Check the vacuum lines for cracks and check for leaks by spraying carb cleaner around the base of the carb and at all vacuum sources in the intake manifold with the engine running. If the idle speed changes in one area, there's a leak in that spot. Another thing to check is the vacuum advance can attached to the distributor. Pull the cap off the distributor and check function of the can by applying vacuum to the hose. You can use a Mity Vac or just suck on the hose with your mouth. If the lever moves the plate in the distributor, it's good, if it won't build vacuum the diaphragm is probably shot and causing a huge vacuum leak.
Mark.

[jdsimon]

I sprayed starter fluid on every vacuum hose I could find and there was no change so I replaced the vacuum advance and that took care of the backfire. Thanks a lot for your help.