Why won't the engine start and run?

Tiny
HISTORYNUT
  • MEMBER
  • 1967 JEEP COMMANDER
I rebuilt the F4 engine for my 1967 Jeepster and I cannot get it to run. It runs fine on starting fluid. It will start and run for about a second then die - even choking it will not keep it running. It has a new coil, points, condenser, spark plug wires and sparkplugs. I rebuilt the fuel pump and it has plenty of delivery and pressure. I rebuilt the carburetor and all works fine. Of all the engines I've rebuilt, this one has me stumped. Any ideas?
Friday, September 21st, 2012 AT 7:42 PM

5 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,871 POSTS
Pop the cover off the carburetor to see if there's any fuel in the float bowl. Any chance there's old gas in the tank? Take a sample, throw it on the dirt or concrete floor, and throw a lit match on it. If the flame goes out, drain the gas tank and refill it with fresh new stuff.
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Friday, September 21st, 2012 AT 7:47 PM
Tiny
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I didn't do the flame test, but I did clean out the fuel system. How long will stored gas last? We always keep a few jerrycans of it around. I pumped some fuel into a jar and didn't see any water in the gas. I'll try your idea.
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Friday, September 21st, 2012 AT 7:56 PM
Tiny
CARADIODOC
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I have a '93 Dynasty with 4,200 miles so you see how often I drive it, and an '80 Volare with 45,000 miles. Both have at least five-year-old gas and they run fine. However, from what many experts have told me is they don't have that kind of luck in their parts of the country. Maybe new gas around here would give me the same trouble but it hasn't happened yet.

This problem occurred to two cars at the dealership I worked for in the '90s. Both came in on tow trucks shortly after refueling. The mechanic spent a whole day trying to figure out the first one. He's the one who did the match trick. On the second car a couple of days later that was one of the first things he did and found the problem.

Water in the gas and stale gas are not the same thing so the fact there's no water in your gas isn't conclusive. If you see fuel spraying from the nozzle in the carburetor but the engine won't run on it, try new gas first.
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Friday, September 21st, 2012 AT 8:13 PM
Tiny
CJ MEDEVAC
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CAN YOU SEE DOWN IN THE CARB TO VERIFY WHETHER THE ACCELERATOR PUMP IS SQUIRTING A PERTTY STREAM DOWN THE THROAT, WHEN YOU ACTUATE THE THROTTLE. DOES NOT NEED TO BE RUNNING TO SEE THIS

THIS WILL, AT MINIMUM, LET YOU KNOW "SOME" FUEL IS GETTING PAST THE NEEDLE AND SEAT AND INTO THE BOWL

WHAT CARB DO YOU HAVE.A CARTER YF?

MINE'S A '46 L-134 FLATHEAD

I JUST RECENTLY BOUGHT 2 FUEL PUMPS ONLINE.$31 A POP. THEY ARE THE GLASS BOWL TYPE.I LIKE 'EM. IF YOURS AIN'T UP TO PAR, I'LL GIVE YOU THE INFO

YOU CAN ALWAYS "JUG IT" WITH FRESH FUEL TO SEE IF THE OLD FUEL IS THE PROBLEM

I HAVE A PIC OF ME "JUGGING" GEAR OIL INTO MY TRANNY---WORKS WELL FOR FUEL INTO THE CARB TOO. THIS HOW MY BUDDY AND I TEST AN OLD CARB/ENGINE OUT IN WHEN WE DRAG IN A WILLYS FROM TIME TO TIME

IS THIS A SHOW PIECE OR A DRIVER?

ONCE WE GET THIS FUEL THING FIGGERED OUT, I'LL SHARE SOME SOME OF MY TRICKS/IMPROVEMENTS, IF YOU ARE INTERESTED

THE MEDIC
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Saturday, September 22nd, 2012 AT 1:54 AM
Tiny
CJ MEDEVAC
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HERE YOU GO---THE PLACE I FOUND THE LEAST EXPENSIVE FUEL PUMP

STILL HERE?

THE MEDIC
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Monday, September 24th, 2012 AT 2:19 AM

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