fighting with engine to idle

[richard2717]

1969 C10 with 307 2 barrel carb. new fuel pump new rubber hoses front and rear. Truck will start up but unless you keep it revving in the higher rpms it will shut off. Hit the accelerator a couple pumps and it will fire right back up but will not come close to idling. What should I be looking for at this point? I swapped the carb from my Blazer and it still does the same thing, but to be fair that carb has sat for a couple of years as well. I don't want to just go throwing parts at it if possible.

Thanks
Richard

[richard2717]

And to be a little clearer, If I close the choke it will stay running but if I even barely open the choke it shuts right off.

[geezer#99]

Vacuum leak.
Since you swapped carbs, I’d think it could be intake gasket.

[richard2717]

Originally Posted by geezer#99

Vacuum leak.
Since you swapped carbs, I’d think it could be intake gasket.

This motor was supposedly just put together by someone else for the PO so i suppose that could be a very real possibility that they did not get the gasket seated right. Are there any ways to tell for sure without pulling the intake?

[geezer#99]

Could try spraying starter fluid at the intake ports. If the rpm increases you have the culprit.
Worst case is it’s on the bottom side of the port and won’t show up easily.

Sometimes you can hear it inside a valve cover.

[richard2717]

I think I have it figured out but won't know for sure until my carb kit gets here from rock auto. The base of the carb I have on it now from the 72 motor, physically bolts up to the intake but is not the same perimeter as the 69 carb. I did not notice the hole being exposed on the right side for what I am assuming is heat riser for a choke. It gets hot enough I could not keep my finger there for long but it definitely has a bad vacuum loss. and it seems to want to run better the short time I had my finger on it. The 69 carb leaks from all the gaskets so I am ordering a rebuild kit from Rock Auto and pray I have the patience to rebuild it. I included a picture of the hole I am talking about.


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[AussieinNC]

Am I seeing a missing carb mount bolt ?

Check that stud mount hole does not go all the way through to the intake plenum.

[richard2717]

Originally Posted by AussieinNC

Am I seeing a missing carb mount bolt ?

Check that stud mount hole does not go all the way through to the intake plenum.

the 72 model only uses 2 bolts to hold down on opposite corners. The 69 used 4. The gasket between the carb and intake is blocked off on those 2 holes.

I will be putting the 69 carb back on once I rebuild it

[geezer#99]

Originally Posted by AussieinNC

Am I seeing a missing carb mount bolt ?

Check that stud mount hole does not go all the way through to the intake plenum.

No you’re not!
Some Rochester 2 bbls only used 2 bolts.