The truck was running fine up until yesterday. It would idle although a little choppy. The gas was old and I have been running it every day while I work on the truck to burn it off. I was down to about 1/4 tank and I added 5 gallons of fresh gas and some sea foam and stabil (blue). Today the truck will not stay running. I can keep it running with a little throttle but it won't idle like it has been. I checked the mixture screws and the left side was out about 4.5 turns. The right side was out about 2.5 turns. I put them both all the way in and started at about 1.5 turns each side. I went all the way up to 4 turns on each side but no improvement.

 

Generally an engine that won't idle is due to a significant vacuum leak.

 

I am planning on a carb rebuild. I thought it would be an Autolite but the stamp on it says Motorcraft. Is this a Motorcraft 2100? I can't find any ID numbers on it. The throttle linkage looks like there are missing parts or is this for different model engines? What are those rubber plugs/caps on the front and back of the carb? Are these where there should be vacuum lines? Where do I hook up a vacuum gauge so I can set the mixture after the rebuild?

 

It would be a good idea to pull out that tank and clean it out or replace it before​​​​​​ you run your freshly rebuilt carb. Replace all the rubber fuel hose, too.

 

Rubber fuel line from the steel tank line to the fuel pump inlet is replaced. I eliminated the rubber line from the pump to the carb and replaced it with a steel line. This appears to be a Motorcraft 2100. I cannot find any numbers on it but the venturi size stamp appears to be 1.21. Is this all of the information that I need to buy the rebuild kit or do I need to find the model number stamp?

 

Those rubber caps are for the heater hoses that used to run to the carb base plate to warm the carb. It looks like that is an older rebuild due to the paper tag. You could just tell them the application and they should be able to get you the right carb kit even though the original tag is missing.

 

What used to circulate through those heater hoses? Was that warmed air from the exhaust or did they route the coolant heater hoses through there?

 

If you ran it real low on gas you probably sucked up some nasty stuff from tank . take a look down inside tank thru the filler . might want to pull tank and give it a good cleaning out .

 

I didn't run it down real low. It had about 1/4 tank when I added the new fuel. I'll take a look in the tank and check the condition of it. The tank looks to be in pretty good condition. A full flush out might be in the cards.

 

Whatever you have in your cooling system.



You can also hook vacuum gauge to manifold vacuum source. Should be a port somewhere on the intake.

 

Is that coolant base plate a separate base that the carb mounts on top of? If I decide to eliminate it do I need another carb spacer plate?

 

May need shorter carb studs but no reason you can't do away with it.

 

Just about any carb kit will work for a 2100, but the quality varies. I think the online carburetor peeps sell a better kit than some of the local auto outlets. The manuals are available for download free in .pdf form they are a wealth of information. The 2100 is popular with the offroad Jeep crowd too, there is a lot of discussion archived in different forums.

 

I'll check it out when I get it off. I am still having trouble identifying this carb. I'm pretty sure it is a Motorcraft 2100 but not sure of much else. I found the venturi stamp (1.21) but I can't locate any other markings. I called an online carburetor parts supplier. They suggested taking it apart and photographing everything before ordering the kit. Does this look original to the truck?

 

That carb coolant base carb spacer may be working in your favor, as aiding in helping your carb from becoming heat soaked. Since no coolant is passing through it.

I removed the coolant hoses on my x-in laws 70 ranger that keep the carb from heat soak stalling.

Orich