Motorcraft 2100 carb

[JustaFordGuy]

A few weeks ago I decided to swap my Holley 2300 2bbl carb with an old Motorcraft 2100. I was having trouble with the choke, and also hard re-start after hot. I rebuilt the carb and installed it. It seemed to run ok but it had a slight hesitation. I tried everything but could not get rid of it. I posted the issue on classicbroncos.com and a member said he had the same problem and it was the float level being too low. I would have never thought this would have anything to do with the hesitation but I raised the float to factory spec and it's gone.

Turns out that the 2100 needs the higher float level so that the emulsion tube holes are covered with fuel. With a low float level the holes are exposed and causes the transition from the idle circuit to intermediate to funtion wrong.

I lowered the float on purpose when I rebuilt it thinking it would help with off camber flooding (works on a Holley). I guess you can't do it with the 2100. It seems to be running much better now but I'll update after I drive it a week or so.

[JustaFordGuy]

Hey Blair, Didn't you say you lowered your float? I wonder if that's why yours is hesitating? May want to check it. We never really tuned your carb when we put it on ether.

[BroncoBlair]

mine hesitates when cold. seems to be fine when warm. i do need to hook up a vacuum guage and set fuel mixture screws.

[JustaFordGuy]

Maybe you just need a choke?

[BroncoBlair]

a choke would help. setting the timing helped some

[JustaFordGuy]

I wonder if the choke from a 2150 would work on your 2100?

[lonesouth]

I think it should

[BroncoBlair]

We can try to install the choke this weekend. Also want to try another driveshaft

[JustaFordGuy]

Can do. We need to measure the drive shaft.

[BroncoBlair]

i can measure tonight

[JustaFordGuy]

Update.
   Float level seems to be very touchy on the 2100. Raising the float fixed the hesitation but it was still hard to start after it was hot (flooding). I took the top back off last weekend and it looked like the float was too high because fuel seemed to be running into the engine through the venturi after it was shut off. I lowered it some and now it doesn't flood as bad and starts easier after it's hot. I think the float level has to be right on the money of else you will have multiple problems. I need to find out what the factory float adjustment is supposed to be. I guess I should have read the instructions? Now I can't find them.