383 stops running after 30 to 45 seconds need help

[bricklayer]

It is a 69 383, holly carb duel feed mech. secondaries the engine fires up and runs fine off throttle and then stops running after 30 seconds or so then all it wants  to do is try and fire but just cranks any thoughts  thanks  tom

[Al]

I had the same problem. It was a worn fuel pump push rod.

[The70RT]

Could be but it should have been a gradual thing. I noticed mine at anything over 50MPH then 40MPH and so on.

[nvrbdn]

i had one do that. as soon as the coil would heat up it would quit running. let it cool down and run perfect. changed the coil and all was good.

[bricklayer]

I'm not running off fuel pump i prime the carb i'm in the middle of restoration and working on engine right now. although how would i chech the coil thanks  tom

[bricklayer]

to be more spefic when i prime the bowls and start it it runs and then it seems to dump all the fuel at one time in the manfoild thanks  tom

[nvrbdn]

are u running something to the carb that holds fuel? the carb alone wont hold enough fuel to keep it running. with a carb set up you can use a small plastic gas can with a fuel fitting screwed into it using gravity feed. make sure the fitting is sealed good. dont need any fires here.

[bricklayer]

yes i'm running an aux. fuel can i am lost with this problem  tom

[The70RT]

yes i'm running an aux. fuel can i am lost with this problem  tom

Maybe gravity feed isn't enough to keep up.

[nvrbdn]

is there anyone around that you could borrow another carb from to see if that fixes the prob? im hearing that the thing fires up on priming then floods the manifold after it runs for a couple seconds. if you disconnect the fuel feed, then start on either, will it idle if you trickle gas into the carb??? or if you are spraying into the carb will it keep running?

[firefighter3931]

How much fuel pressure are you using ? It will run off the fuel in the bowls for half a minute but you might be pushing the floats up too high (excessive pressure) and flooding it. Holley carbs like 6-7 psi.

I've ran a few 440's with a gravity feed setup....works ok at idle but revving it up will empty the bowls pretty fast. 



Ron

[bricklayer]

Ok without a fuel pressure gauge how would i go about setting the float level so i know i'm right there   thanks tom

[bricklayer]

Also anybody live near lititz,Pa. that could lend a helping hand  thanks tom

[firefighter3931]

Ok without a fuel pressure gauge how would i go about setting the float level so i know i'm right there   thanks tom

Holley carbs have a sight plug on the side of the bowls. Remove the plug and adjust the level using the nut on top of the bowl. The set escew has to be loosened off first. Turning the nut clockwise lowers the float....counterclockwise raises the float. The fuel should be just at the bottom of the hole.



Ron

[bricklayer]

How do i adjust my float before there is any fuel in the carb? thanks again tom

[firefighter3931]

How do i adjust my float before there is any fuel in the carb? thanks again tom

Tom, you can fill the bowls using the vent tubes. Just pour some gas in there using a small funnel or even a turkey baster. I suggest you buy a new baster or the wife will have your head on a platter, lol ! 


Ron

[bricklayer]

i'm sorry could you please walk me through this? when i fill the vent tube with fuel how do i know where to set my float so i know the float is set at proper height  tom

[The70RT]

i'm sorry could you please walk me through this? when i fill the vent tube with fuel how do i know where to set my float so i know the float is set at proper height  tom

Like firefighter said -

Ok without a fuel pressure gauge how would i go about setting the float level so i know i'm right there   thanks tom

Holley carbs have a sight plug on the side of the bowls. Remove the plug and adjust the level using the nut on top of the bowl. The set escew has to be loosened off first. Turning the nut clockwise lowers the float....counterclockwise raises the float. The fuel should be just at the bottom of the hole.



Ron

[bricklayer]

I'm not trying to sound ignorant but let me ask this question a differnt way how would i set the foat level with carb on work bench thanks again for the reply's so far  again thanks for your patience  tom

[The70RT]

I'm not trying to sound ignorant but let me ask this question a differnt way how would i set the foat level with carb on work bench thanks again for the reply's so far  again thanks for your patience  tom

I would say use a float gauge but you will have to get specs. Maybe you can use gravity feed also and do as was mentioned previously with bowls still attached.