Thread: Carbed 305 dies soon after starting

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I have a 305 that i just built. everything on it is new. It has an Edelbrock 600 cfm and is running this Fuel Pump

As soon as i start the engine it runs fine for about 10 seconds and then dies. If I give it some gas it will postpone it from dying until it gets back to idle and then dies again. Fuel Pressure at the carb is 6 psi.

What should I do?

Thanks,

Sounds to me like it is as simple as adjusting the choke for cold start operation.

It's an electric choke and I tried it plugged up and once again unplugged. Is these something i need to do to it?

Did you try loosening the screws on the side where the round plastic piece is and turning it so the choke flap is open on top of the carb???
Also since it's a new motor it could be a little tight and needs to run at about 2,000 to 2,500 for about a half our.
Shut it down if you need to adjust anything during that time or it has a problem like over heating.
You should not let a new motor idle in the first half hour or so, at least I don't anyway.
Kurt

Is there a vac leak?

Gotta sqwirt bottle or a water hose???
Hear a whistle???

Floats stuck???

vara4:
On the initial startup i did the whole pulsing session that is needed to break in the cam. I'll check the flap screw.

pro70z28/vara4:
I dont hear any whistling and all my lines are new and tight but just in case whats the best way to check for vacuum leaks?

cffisher:
Could the float be stuck on a new carb?

Thanks Everybody,

Sure can....Why not??

I'll check all these when i get home from work..

Some people tell me it could be air/fuel ratio because i didnt set it i just bolted the carb on. Could that be it?

Also is that fuel pump big enough? The engine is in a truck and the gas tank is between the frame rails behind the axle. i was thinking maybe I need a new pump.

Thanks

Sounds to me like your runing out of gas.. 6 psi should be good. if floats are set to low or stuck you'd run out of gas. OR a real bad vacume leak. PCV bad? leak in intake gasket there are many reasons it will start and die.

To find an external vac leak I spray a little starter fluid in suspect areas. If there's a leak the RPM's will rise when it sucks the SF in.

Might be wrong, but I think 6 psi is too much for an Edlebrock, drop it down to 3 1/2 psi.

What ever it is please let us know when you get it figured out, Thanks.
Kurt

Just read this thread and most have covered the obvious – here’s my two cents:

I’m assuming we’re talking about a 1406 here. They’re typicayl a great unit from ease of installation and long trouble free operation. I find them to be a bit rich out-of-the box sometimes, but that can easily be addressed with jets and rods.

6 PSI is boarder line on the high side with this carb – I wouldn’t probably go as low as 3-½, but would go down to 4-½ or 5 PSI. Do you have an actual gauge in the fuel line just before the carb?

The fuel/air ratio should be fine out of the box. If you’ve messed with it, gently bottom both idle screws and back out 1-½ turns and that will be fine for this application. You may need to “fine tune” after you get things running well.

Ten seconds is just about what it takes to empty the fuel bowl. As such, I would suspect the following:
1. Crud in the fuel screen assembly where the fuel enters.
2. Stuck or hanging float – Possible but not too likely on a new unit
3. Mis-adjusted float - Possible but also highly unlikely on a new unit
Did you put a new fuel filter in between the fuel pump and the carb? If not my money is on number 1 as there is a very high probability that sediment from your fuel tank has passed into the carb and some woolly-buggers have lodged around the screens (there’s two of them) that actually protect the needle and seat assembly in this carb.

If you don’t have a good fuel filter and in fact crud has entered into the carb, the only way to remedy the problem is to remove the top of the carb and very carefully remove the floats, then the needle valves and unscrew the seats to allow the screens to drop out. This is best done in a very clean and well lit setting and if you’re not familiar with the carb, download the manual from www.edelbrock.com as it contains some real helpful information and pictures.

Good Luck,
Glenn