Engine quits ~10 seconds after starting

Is this only when idling?

What does the car do on the highway?

Speedy Jim

You can work either the pedal or carb and increase the RPMs. Which increases the RPMs without hesitation. Regardless of engine speed, in about 10/15 seconds it is - once again - shutdown time.

I presently cannot get ithe bug running long enough to leave the garage. Prior to this problem the engine was reliable and had no problems at highway speeds. Although as a daily driver the top speed was generally around 45/50 mph.

Thanks Speedy Jim for reading my earlier post.

Man, it still smells like fuel starvation.

Are you up to a minor machining job? Take out the carb bowl drain plug. Drill a hole big enough to stuff a length of clear plastic hose into (small diam hose). Secure hose vertical. It will act as a manometer to read fuel level.

The level should be rock-steady when running. If you see the level falling and then it dies, it is starving.

If that test shows nothing at all, I would "instrument" the Ignition circuit. Hang a voltmeter on the Coil (+). Hang a 12V lamp (better is a 12V LED) on the Coil (-) to ground. Does the lamp keep flashing *after* the engine begins to die? IOW, is it still getting spark whilst gasping its last?

Jim

Sounds like a good test. I will give it a try. I have checked the float bowl after the engine conks, but have done no test which would verify the fuel system.

Slick. Sounds like a good way to check the carb.

So far I have not found a problem with the electrical system. I went so far as to wire 12v direct to the battery and to a switch/fuse. Replaced the hot 12v on the coil with this test wire. Cranked the starter and flipped the switch. Engine ran for 10 seconds and then conked. You're right. That sounds like a possible fuel problem.

Thanks again.

Is the wire to the fuel-shutoff good? It's near the base of the carb.

Fuel pump pushrod worn down/bad fuel pump? Sounds like a loss of fuel to me. Regardless, if you pull the fuel line with a full fuel bowl it should run for more than 10 seconds at idle on the fuel that is in the bowl. I would say start it up, let it run until it dies and then disconnect the fuel line and pull the top off the carb. If there isn't any fuel in the carburetor then you can narrow things down to an obstruction in the tank, lines, pump, or float valve.

Chris

what about the carbon filter for letting air into the gas tank to replace used fuel?

This is a long shot but.... I had a similar problem with a 74 bug. Hit the accelerator to give it a shot of fuel, cranked it up and as soon as the douse of fuel from the accelerator pump was gone the engine would die. Turned out to be deteriorated boots on the intake manifold sucking air through splits in them. After the initial dose of gasoline (rich running condition) the engine would simply starve for fuel be cause it was sucking air through the boots. Changed the intake seal boots and had no more problems. Good luck and let us know what solves it! Charles

check that ground wire from the transmission to the frame

how many wires do you have going to the ign. coil? 2 to the (+) side and 1 to the (-) side?

do you have the correct fuel in the gas tank? I would use a hose and a semi-full gas can and hook that to your fuel pump to make sure that is not a fuel problem from the tank. Some people use a gas can that is higher than the carb and allow a siphon effect to happen so the gas flows freely to the carb bypassing the fuel pump. OF COURSE USE COMMON SENSE AND SAFETY!

has to be something simple!

The mainfold boots appear to be OK. I checked them over and reinstalled them after adding a set of reman heads last winter. I usually change the boots when I slap the engine back together, but didn't have a new set at the time. I did check and tighten them down, but it might be time to take another look.

Interesting. I have not looked at that recently. Which I will at my next opportunity.

On the (+) side, the hot 12v, one [Y] connector to both the carb electro solenoid and the choke, one to the compufire connection. On the (-) side, only the compufire negative connection.

I learned the hard way only to purchase branded gas. That is, gas from a major station and not an off-brand. Last fill was from the same Chevron station I've used for quite a few years. Still, if the stations tanks are low I know that it is not uncommon to add both moisture and crud during the fill.

Good idea. I have not seen any indication that the pump is the problem, but it can't hurt to check.

Interesting thought. Although a current work schedule has interrupted my garage time, at my next opportunity I do plan to use Speedy Jim's suggestion to check the gas level in the float bowl. Might also be a good time to see there are other circumstances affecting the carb.

Thanks to all of you who offered suggestions.

Wrapped up the intake manifold boots. Good idea, but it made no difference.

Another good idea. I checked the grounding strap and the fastener. Looked OK. Pulled the nut, checked the connection and reseated the strap.

Pulled the 009 with the compufire and installed the SVDA with new points, condenser, and rotor. Engine now is able to idle past the usual 10 seconds cut-off. Go figure. I have never before had a problem with the compufire module, and wonder if something is wrong with that unit. Past checks found that the ignition made no difference, points or pointless, 10 seconds to stall time. Now to try a test drive and see if the engine cooperates. BTW: set timing w/SVDA to max of 28/30 degrees.