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I have been having issues with a truck that idles great then bogs down under partial throttle when under load, and by that I mean when placed in gear. I have worked through a few other suggestions such as fuel lines, fuel pump and filter issues. Nothing seems to have fixed the issue and I am leaning now towards a choke or potential lean issue. I noticed that as shown in the pics below the choke plate in my 2100 carb never closes. Even when completely cold it never moves, it just hangs slightly open all the time as shown in the pics. The other day I started the truck and held the plate closed and the truck did not bog down when under partial throttle it ran quite well. I am sure that I am now getting quite close to figuring this out but any help would be appreciated.
This plate is always open like this, never closes even when cold
Rotating the black cap adjusts the internal spring.... if it even has one. Check if it does. The cold setting is a one-eighth inch gap btwn the plate and the air horn. The cap or spring could also be indexed wrong such that no choke action happens.
That choke is indexed wrong and the hot-air stove is missing, which under normal conditions would prevent it from ever opening. Looks like someone noticed that, and their "fix" was just to force it open all the time by rotating it over-lean. You need to use a hot-air stove repair kit or bulk tubing to fix.
Sorry but I have no idea what the hot air stove is, do you have a pic that could show what it is. Also any idea how I remove the 'over lean' condition I apparently have
The choke cap "index" controls its position when cool, and how much heat is required to open. Yours is set all the way back such that it's open even when cool.
Please see this write-up with regard to the choke cap index:
The choke spring is bimetallic is designed to expand and contract with changes in temperature. The spring has a hook (tang) has to be indexed so as it heats and cools it actuates the choke plate.
Much homework on your end to understand its theory, design, and operation. 2x with FMC.
Wow I am really out of depth on this truck. Maybe it just needs too much work for me
I tend to agree, lol.
I have owned my truck a year, and have been fixing something every weekend, it seems, just to keep it on the road.
It would be "fun" if this was a second vehicle, but this is my daily driver.
But, if it hadnt been for the great people here at FTE that have helped muddle me through, i woulda given up long time ago.
