I took my carb off and cleaned it like it was going in for surgery. It's a motorcraft 2100 2 barrel and it's on a 304. The Jeep had sit for along time, at first it run ok all things considered but it run rich. It seemed to get worse, I adjusted the mixture screws but didn't do much for it. Last weekend it had gotten to the point it wouldn't idle. Anyway I put the kit in it and changed the power valve. It's way better, I'm still tweekin' on it but not satisfied yet. The way it is now, it's idle is a little rough and seems to surge a bit every now and then when driving. The surge, I need to drive it a bit more to tell exactly when it happens. The main jets are stamped 45F, is this right for a stock 304? What RPM is it suppose to idle at?
Rebuilding a motorcraft 2barrel
- Thread starter flatie46
- Start date
Robert_Stephens
New member
Boy, your post sure brings back the memories for me back when I had a couple of the 304s in a few Jeeps back, and had to fiddle with that stock 2 barrel carb. Your rig should idle at 650 RPM. The surge is because the float and arm is not that great and poorly designed for a rig that does what Jeeps do, short wheelbase and all.
The stamp of 45F is correct.
Also, those 304s are notorious for breaking the timing chain and should be replaced with the aftermarket gear driven set up.
You may wish to consider replacing the stock carb and get a Holley 390 4 barrel, off road kit installed, Clifford Headers, and remember to install 2 fuel filters in the line before the feed line runs into the carb. These mods and that carb will help a lot and makes the Jeep run very very smooth and trouble free. I love my set up in my Jeep, VEX, and it has run for years now flawlessly, with the inline sixes I run.
Just an option for you.
Let us all know how it goes.
Robert
I've heard everything from one extreme to the next about the Motorcraft carb. I've read about people making minor changes, like two stage power valves that really help fuel economy and how they had a recall to install the spring to deal with float bounce. Then I've heard they were only good to scotch you Jeep with by some. I guess I'll develope my own opinon as I try to work the problems out, I think I've found some of the problem, I'm pretty sure my vac advance vaccume line isn't routed right. Gonna check it out next chance I get. As far as changing to a different carb, that may happen but I'm pretty hard headed when I'm tryn' to fix something. If I give up on this one you can rest assured it's a POS. If it can be made to work like AMC intended it to I can do it. I would much rather fix what I have than give $400 for a new carb. Thanks for the help, wish me luck.
Okay, I've found an intake leak. Pretty much all the way around the intake. That'll make a carb hard to tune for sure and probably why it doesn't want to idle below 1000RPM. Well now I know what I'll be doing this weekend. Oh well, as long as I've got a Jeep I've got something to do. Kinda like having anthor kid or something.
black87yj
New member
i run a motorcraft 2150 with 050 jets on a mopar 360 . are these the right size ? it idles fine but runs a bit rich ans has a slight stumble off the line and around sharp corners. probably look at the float 2marow, but as long as i,m in there i'd swap jets if there is a better size you guys would recomend.
Been busy but finally got back to workin' on my Jeep. Replaced the intake gasket and it was definitely bad. When I started it I could tell pretty quick how much better it run. Got it warm and set the idle, drove it stopping every so often to tweak the mixture. I have to say it runs pretty darn good. Most would leave it alone but I'm still gonna play with it and may buy a two stage power valve. I want the best fuel economy I can get out of it. Glad I didn't just go buy a carb, I'd still have the same problem and be out 3 or 4 Ben Franklins.
