Question about 1988 Chevrolet Silverado 2500
Sounds like a flooded carburetor. Possibly float needle dropped since bowl was not full enough to keep float needle in place. This could be from improper adjustment during carburetor overhaul. When floats are set, some have adjustments for both top cutoff and bottom drop.
Now if black smoke is not from exhaust pipes, you have a bigger problem. Could new fuel be contaminated with diesel? Also depending on carburetor type, the rear barrels of a 4 barrel carb can soot up if the rear barrels are not often open. Some rear barrel actuators are vacuum operated, others are mechanical links.
Some other thoughts are metering rods can be extended and jam if either the seat unscrews or the rod hangs up. Not common, but possible. Free floating rust could jam the metering rod in almost any position. When placing a carburetor on the intake manifold, NEVER turn the carburetor upside down or at any angle that the truck would not normally go. The float pin can slide out of some models.
Also, was the gas used from a 2 cycle engine like a boat or lawnmower that has oil in the gas?
Posted on Sep 17, 2012
SOURCE: car will start but wont stay on
Idle adjustment. You didn't state the vehicle, so I will post two possible solutions.
Fuel injected engines typically have an IAC valve in the throttle body. This valve adjusts the throttle plate to be open to a certain extent. The computer can control this valve as need based on the density of oxygen in the air. Remove the throttle body and clean the IAC valve or replace it if necessary. Mechanical (gas engine) experience necessary.
Carb engines typically have an idle adjustment screw on the exterior that may need adjusted. Mechanical (gas engine) experience necessary.
Posted on Dec 30, 2008
You've done a lot of work. How does your EGR valve look Its the 'space ship' gizmo under the air cleaner. Remove and decoke is a quick job and it may just cure the lot
Posted on May 07, 2010
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