Got my motorcraft carb!

[nica89yj]

Today I went looking for a replacement motorcraft carb and after shopping around for a while I found one and bought it. The guy told me it came off a 68 ford V8, the venturi reads 123 or atleast I think its the venturi. Its going to go on a 4.2 89YJ and I know u guys recomend a 108 venturi, Is this going to hurt performance? should I change something? The carb seems to be in very good condition and moves freely, There is a broken little steel connector that helps open the air trap door, Is this carb gonna work fine???

[wm69]

It outta work ok, but with 1.23 venturi you're gonna be running rich unless you've modded your engine. You might get away with it like it is, you might try rejetting it, and worst case scenario you might not get it tuned and have to try to find a 1.08 or a 1.14. Click on my username and "find all posts" and you'll see some recent posts that will include links for doing the swap. Good luck.

[nica89yj]

Anyone?? I think your all bored of me asking so much!!

[nica89yj]

WM69 thanks for your help. I think Iam going to stick with the 123 venturi carb rebuild it and if does not work i guess ill go hunting for another one. If i rejet the carb will this fix the venturi problem? theres a guy on ebay selling the jets for 24 dollars should i buy these???

http://cgi.ebay.com/ebaymotors/JET-K...spagenameZWDVW

[wm69]

That's about right as far as price goes. Put the carb on and see if you can get it running first. Check what you have now and if it's running rich you know you need to get 3 sizes that are all smaller than your current size. Mine's got 47's so I'd probably get 43,45,46. One of those should work and doing it that way will allow me a little more room to work with when trying different sizes. If you take the top off of your carb (6 phillips screws) you'll see the bowl (has a float in it). Take the float out (after looking at how it's mounted so you'll be able to put it back together) and the jets are screwed into the bottom of the bowl. They have a number stamped on them. Get the carb going and if you're running rich go smaller than you currently have. You don't want to go too small so go down in small increments. You might check with that seller and see if he'll sell you more than 3 sizes and give you a price break if your stock set of jets doesn't end up working. To answer your question, I'm not really sure. I know people have used the 1.21 and it's worked ok so you SHOULD be ok. Rejetting will decrease the fuel flow to some degree but it's not going to greatly change the amount of fuel you're getting.

[nica89yj]

Cast Number = CFM
.98 = 190
1.01 = 240
1.02 = 245
1.08 = 287
1.14 = 300
1.21 = 351
1.23 = 356
1.33 = 424

These are the venturi sizes on the motorcrafts right, 1.08 is the preferred size because its the closest to the 258? making the 1.14 the next best carb size to get if the 1.08 is not available? Still trying to figure out if the 1.23 carb i own will work on my jeep, thanks guys.

[wm69]

Originally Posted by nica89yj

Cast Number = CFM
.98 = 190
1.01 = 240
1.02 = 245
1.08 = 287
1.14 = 300
1.21 = 351
1.23 = 356
1.33 = 424

These are the venturi sizes on the motorcrafts right, 1.08 is the preferred size because its the closest to the 258? making the 1.14 the next best carb size to get if the 1.08 is not available? Still trying to figure out if the 1.23 carb i own will work on my jeep, thanks guys.

There was someone on this board who used a 1.21 and said it worked fine. I had the post saved to my favorites on my computer but the thread won't pull up with the link anymore since they changed the board over to vbulletin. I've got a 1.08 on mine and have a 1.21 I plan on using if my weber ever craps out (since the weber prices have gone through the roof and I can work on/tune the 21XX carbs).

[nica89yj]

I was wondering what the motorcraft carb is made off? alum?