Drilling out Venturi tubes in Carter carb - JeepForum.com
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post #1 of 9 Old 05-20-2003, 04:22 AM Thread Starter
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Drilling out Venturi tubes in Carter carb

I have a stock '83 CJ7 6 cyl and carter carb. I removed the venturi cluster and ran needles through the venturi tubes to clean them out. I read on another forum that Jeep recommends you drill them out to 0.032 inches and your engine will idle better and not stall (like mine does).
Here's the ?, where do you get a 0.032 drill bit ? By my calculations thats a 1/31.25. I don't think I've ever seen that size. Are they really referring to a 1/32 bit? Has anyone ever done this, does it help? Should I stop asking questions now so someone can answer this?

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post #2 of 9 Old 05-20-2003, 08:26 AM
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try a set of number drill bits from 61 to 80

1978 cj-7 had since 1979
401 .030 over- full floating flat top pistons
crower solid cam 292 dur .500/.510 lift
turbo 400 tranny 2500 stall
model 20 transfer case
aj delux glass body
4" lift
dana 30 frount
dana 44 rear
4.56 gears

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13.461 @ 92.45 mph on 37" super swampers on 1/4 mile
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post #3 of 9 Old 05-26-2003, 10:20 PM
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Got mine at ACE Hardware and drilled em out. Runs a little better but doesn't solve the problem. It does help...

Capt. Trip Franklin
Florida Down Under, Inc.
84 CJ7//258//T-176//Dana300
31 AT's//Nutter Bypass
TFI upgrade//Sway Bars Removed
8000lbs Winch//SOA in the works
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post #4 of 9 Old 05-27-2003, 11:12 AM
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I too just had to do the drill out of the idle jet fule pick up tubes. the drill is a #67 that I had no problem finding at local hardware store. Seems to have fixed the idle issues.....

84 CJ7 Laredo 258/T5 herced tub 86/D44 4.5"RE lift, 33Xterrains and a TWoods CV driveshaft Custom bumpers and tire rack.Blue Jeep Club #140
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post #5 of 9 Old 05-28-2003, 05:07 PM
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The best thing for that Carter is to use as anything esle but a carbuerator!!! For 119 bucks at Autozone, you can get a motorcraft carb that will run exponentially better than that carter EVER will. Of course, I did the swap as I was completing the nutter by-pass. Total cost of the project was less than 175 bucks. Been on two very serious trail rides so far and it has by far been the best carb I've ever experienced off-road. Even better than the 385 dollar webber!

What you need is a MC2100 carb w/ 1.08 venturi size (I used one of an 1975 CJ5 w/ a 304)
Mr. Gasket adapter PN 1875 (i think)
5 1/8" air filter assembly.

I'm telling you... ditch that Carter...best thing you can ever do for that 258

85 CJ7 Laredo Hard Top
33" BFG M/T
Moser One Piece Axles
D300, D30, AMC 20, 258 ci
Motorcraft 2100 swap
Nutter By-Pass
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post #6 of 9 Old 05-28-2003, 05:50 PM
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Don't forget the ignition system, either.

I rebuilt my stock carb, and it ran much better.

I still thought it should idle/run better.

I read that the high mileage Duraspark ignition system could cause idle problems, as well as many other performance/driveability issues.

I installed GM HEI, and this jeep has never run better.
All my idle problems, as well as many other performance issues, are gone--and I am still running the Carter carb.

Yes, I want to upgrade the fuel system, but I have a long list of what I want... :-)


Hope this helps
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post #7 of 9 Old 05-28-2003, 09:34 PM
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I plugged the ports that the "stepper motor" on the back of the Carter operates and also performed the "Nutter Bypass" and my '86 258 runs flawlessly and gets great mileage. Open the hood for the "Smog Police" and everything looks TOTALLY stock! Also, if it ever comes to it I can UN-modify my system in about an hour for $0.00...

Bruce from West LA (Lower Arkansas)
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post #8 of 9 Old 05-29-2003, 10:31 AM
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what is a nutter bypass?
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post #9 of 9 Old 05-30-2003, 05:01 AM
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How is the Jeep running...are you divorced yet? This is the Nutter Bypass.

...The Carter is junk..dont waste your time drilling....my MC2100 is simple, cheap and runs like a top. Around $32 on ebay and $16 for the rebuild kit at advanced auto

Last edited by sampson9dk; 05-30-2003 at 05:06 AM.
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