Engine starts ok, but immediately stops:

[fussfeld]

Next Crisis:
As you may know, i've swapped a 4.3 in where a 305 was. Anyways i can get it to start up pretty easy, but it immediately stalls out---like after only a split second to 1 second.

i'm leaning/hoping maybe the timing is too retarded; When i was messing around with the distributor, constantly taking the cap off and doing tests (see other post entitled "no spark, no tach signal") the distributor did move---apparently wasn't tightened down well.

i don't think it's fuel or the choke---it's pretty warm here right now. Plus, i experimented with the choke. Opening it all the way, opening it a little right after startup, keeping it closed. But all still the same results.


Thoughts?

 

[89Suburban]

Sounds like it is only running with the key in the crank position then?

 

[fussfeld]

The thing is i have an underhood starter hooked up, so i put the key in the run position before cranking.

Now a few days ago i WAS using only the key and yes it seemed to only run in the start position. But really it stalls out so fast it's almost like i don't even have time to release the key before it stalls.

BTW i advanced the timing a little today but it didn't help.

 

[fussfeld]

Ok, i got it solved (i think/hope?)----there wasn't enough fuel in the bowl. So this time, i am filled it up all the way thru the vent hole.

It ran much longer this time. It did cut out after say 3-5 secs but i think this is due to the fact that this is the first time it has really run since oct 13.

 

[fussfeld]

i've spoken too soon; i can't get it to keep running for more than 3 seconds or 6-7 revolutions.

quadrajet (originally off of a 305)
HEI

4.3 v-6

 

[bucket]

Will it keep running as long as you are manually feeding it fuel?

 

[fussfeld]

Will it keep running as long as you are manually feeding it fuel?

How?

 

[bucket]

In my junkyard days we used a mustard bottle with fuel in it, just keep squirting some in every second or so to keep it running. Or use a can of starting fluid. Either way, have a fire extinguisher handy just in case.

If you can keep it running with fuel, you know you have a fueling issue.

 

[fussfeld]

Not sure i want to do this due to safety reasons. Also, i can't hook up a remote starter properly(not enough space) and i don't have a helper.

But the bowl is full because each time it stalls i can see fuel squirting in when i move the accelerator arm.

 

[chengny]

A full carburetor bowl doesn't go dry in 3 seconds/6-7 revolutions.

And the fact that the accelerator pump is still able to squirt gas into the throat - after each stall event - would confirm that there is sufficient gas in the bowl. And that gas is probably coming from the fuel pump.

But, just to verify fuel pump operation; pull the gas line from the carb inlet, attach a hose to the line. Lead the hose into a container and crank the engine for a couple of seconds. If you get even an ounce or two of gas in the container...the pump is supplying the carburetor with gas at the specified rate.

So if the fuel pump is pushing gas into the carb and the accelerator pump can pump it down the throat, you might have look at cleaning the carb (internally).

But first, you should try some ether like Andy suggests. There is nothing inherently dangerous about using it - that's why they sell it. Just squirt some down the throat and crank the engine. When it fires up, just keep giving it small short squirts of ether to keep it running while you try to figure out what's going on.

 

[fussfeld]

UPDATE:
i was able to keep the engine running by repeatedly pumping the throttle. Engine did not run smoothly, of course. But it did continue to run.

What would this tend to indicate?

 

[chengny]

You were running on the fuel injected by the accelerator pump. It would appear that your jets are completely blocked. The carburetor will have to be pulled and cleaned.

I have to ask, did this just suddenly happen all at once? Or did you notice that it was getting harder and harder to keep the engine running until finally it just won't idle?

Just check to be sure someone didn't tweak the idle screws all the way in. Use a screwdriver to gently bring each screw to the fully in position. Don't crank on them. Then when it is bottomed out, turn the screws CCW about 2 turns. That is a good rough setting for a Q-jet idle mixture screw.

 

[Georgeb]

Another possability is a large vacuum leak. Are all the lines connected or the ports plugged, PCV valve good? Also check the gasket on the base of the carb and adapter plate if you have one for a proper seal. It sounds like you aren't getting enough fuel to keep running and by pumping the accelorator you are enrichening it just enough to overcome it to stay barely running.

Is there another thread that outlines your carb setup? If not what setup are you running. The more info you can give the better.

 

[fussfeld]

You were running on the fuel injected by the accelerator pump. It would appear that your jets are completely blocked. The carburetor will have to be pulled and cleaned.

I have to ask, did this just suddenly happen all at once? Or did you notice that it was getting harder and harder to keep the engine running until finally it just won't idle?

Just check to be sure someone didn't tweak the idle screws all the way in. Use a screwdriver to gently bring each screw to the fully in position. Don't crank on them. Then when it is bottomed out, turn the screws CCW about 2 turns. That is a good rough setting for a Q-jet idle mixture screw.

Another possability is a large vacuum leak. Are all the lines connected or the ports plugged, PCV valve good? Also check the gasket on the base of the carb and adapter plate if you have one for a proper seal. It sounds like you aren't getting enough fuel to keep running and by pumping the accelorator you are enrichening it just enough to overcome it to stay barely running.

Is there another thread that outlines your carb setup? If not what setup are you running. The more info you can give the better.

The carb was rebuilt by me in Jan 09, then run briefly on a 350--- carb ran ok. The carb has been sitting on the shelf since then to about 3 weeks ago.

The idle screws are not all the way in---checked that a few days ago.

All the vacuum ports that i know of are plugged. How to check if the pcv is good?

Will check for vacuum leaks soon.

 

[Georgeb]

The pcv should rattle when you shake it. What kind or carb on what intake?