Very fast idle on start

[MDC82]

1982 C10 straight 6 cylinder all factory stock old farm truck. No cruise or other extras. Winter or summer it started every time and ran great. When replacing water pump I noticed some seepage around carb gaskets so got a carb kit and replaced them. I also replaced vacuum lines as most of them were cracked and brittle.

Now when starting it revs extremely fast. I can get it to slow down by a pump on the pedal but it won't drive without dying until the engine warms up. Electric choke works and eventually when engine warms up it runs fine.

Seems like a very complicated carburetor for such a simple motor. Should have left it alone. Please help. Thanks.

 

[YakkoWarner]

If giving a tap on the pedal slows it down, could be something simple like a linkage binding. I'd start by verifying everything moves freely and smoothly.

 

[Ken B]

Vacuum leak?

 

[Trucksareforwork]

If it runs fine after warm, then start with the obvious: is the fast idle screw too high? Thats the idle screw that contacts the cam on the choke linkage.

 

[DoubleDingo]

I'm guessing it's a vari-jet. Probably has provisions for fast idle when cold started. The literature about the carb adjustments may be here in the library. If not, a simple search on the webs can yield sources for it, either for free or for purchase.