I got a new carb put on my Duster because the old one failed under warranty. It runs fine except that if you turn it off and let it set for a while, the choke mysteriously closes, even when it is hot. The other day it would not start at the grocery store. I propped the choke open and it cranked right up. It sputtered and ran bad for 15 minutes afterwards and then ran fine. Any suggestions?

_________________
82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

It sounds like the choke spring (stove) is set too tight. If you remove it from the exhaust manifold and look at the underside closely you will see some "R" & "L" marks for rich & lean, loosen the nut and rotate the plate to reduce the spring force.
http://www.slantsix.org/articles/choke- ... adjust.htm
DD

Ummm.... he said this is on a Duster. That puts it in the 1970's and those choke thermostats are factory calibrated and made NON-adjustable so no one messes up the emissions calibration.

Just thought you'd like to know.

Good point about the later choke springs not having an adjustment.
Take a look at it, if it does not have an adjustment nut then all you can do is to try to take some tension out of the spring by over-winding it tighter or bending the mounting tabs.
DD

Isn't there an electrical choke assist on newer thermostats. (that wire does something?)

I don't really understand how it knows when to work or how to test for proper operation. (not that I'm currently having a choke problem luckily)

How should it work, and could this be his problem/ solution?

_________________
1980 Aspen 225 super six

The electric assist is connected to a thermostat. The slants have it bolted to the top of the cylinder head in the rear of those two holes in the top of the head between the valve cover and manifolds. The thermostat activates the electric choke above 50º to 60º. The exact temperature is published in the service manuals. The early style choke thermostats are a rectangular style thing. The later ones are a little round thing.

The power to the thermostat comes from the ignition run circuit. by the 70's they used a 3-terminal oil pressure switch (in addition to the thermostat) and ran the electric choke power through that so it only got power when the engine was running. Seems some people have a habit of leaving the ignition switch in the "run" position without the engine running and this kept power to the electric choke and made the choke open which in turn made for a hard starting engine.

I fixed it, I unhooked the choke. I really did'nt need it anyway. If you pump the gas rapidly while cranking it will fire right up. If I remove the choke blade, will it give me any extra horses or gas mileage, and if so, do I have to re-jet the carb?

_________________
82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

Removing the choke blade will not give you any power or change the fuel mileage. Perhaps leaving it there will direct and streamline the airflow and already be giving you the mileage and power increase are seeking !!