Here's why:
* Electric Choke Function: The electric choke warms up the carburetor's choke plate, which restricts airflow when the engine is cold, allowing for a richer fuel mixture to aid starting. This resistor controls the current flowing to the choke, regulating its heating rate.
* Starting Problems without it: Without the resistor, the choke might receive too much current, causing it to overheat and potentially damage the choke itself, or it may not warm properly. A malfunctioning choke can lead to difficulties starting a cold engine because the mixture may be too lean (not enough fuel).
* Why your truck *might* start: If your truck *does* start (though potentially poorly), it's likely that the choke is opening enough or that other factors (like a warm engine) are compensating for the missing resistor.
In short: The missing resistor isn't the *direct* cause of preventing starting but is an essential part of the cold-start system. Its absence may make starting difficult, especially when cold, but it won't necessarily prevent starting completely in all situations.
You need to replace the resistor. Find a replacement with the same resistance value (usually printed on the original resistor). You'll want to find out the original resistor rating (Ohms) before ordering a replacement. A local auto parts store should be able to help with this. Incorrect replacement could cause further problems.
