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Unread 09-16-2013, 11:41 PM   #1
c5wagner
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1989 YJ Wrangler 
 
Join Date: Sep 2013
Location: Reno, Nevada
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Need help with High idle after mc2100 swap

I recently put a mc2100 with 1.08 venturi and size 48 jets in my 1989 jeep wrangler with the amc 258cid motor, but the thing will not idle below 1200 rpms. I checked all the vacuum lines and there are no leaks, the manifold to adapter and the adapter to carb all showed no signs of leaks with carb cleaner either. I plugged up the choke hole at the carb base and got a manual choke and that didn't change anything. My timing is set at 8*. Has anyone else had anything like this?

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Unread 09-17-2013, 12:05 AM   #2
booboowv77
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How about your fast idle screw?
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Unread 09-17-2013, 12:07 AM   #3
c5wagner
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Quote:
Originally Posted by booboowv77 View Post
How about your fast idle screw?
removed it trying to get the idle down, no effect
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Big Red Money Pit: 1989 Base YJ, 4.2l, MC 2150, nv3550, nv241or with 4:1 low, 2003 Rubicon f D44 & r ford 8.8 with 4.10 gearing, Skyjacker 4" double military wrap springs, RC perf. 2.2 shocks, homebrew 1/2" lift boom shackles, 31x10.5r15 Treadwright Guard Dogs.
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Unread 09-17-2013, 12:30 AM   #4
booboowv77
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Does your throttle cable have slack in it or is it tight? Something is stopping it from going the whole way down.
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89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
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Unread 09-17-2013, 12:36 AM   #5
booboowv77
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Also try backing off your fuel mixture, mine is only 3/4 of a turn out but I am running a 1.14 venturi.
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GOOGLE IS YOUR FRIEND!!!
Just my toy!
89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
Built not Bought #759
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Unread 09-17-2013, 12:38 AM   #6
c5wagner
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Location: Reno, Nevada
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I've gone in and out with minor changes made. I think I'm going to try decreasing my jet size from 48 to 46
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Big Red Money Pit: 1989 Base YJ, 4.2l, MC 2150, nv3550, nv241or with 4:1 low, 2003 Rubicon f D44 & r ford 8.8 with 4.10 gearing, Skyjacker 4" double military wrap springs, RC perf. 2.2 shocks, homebrew 1/2" lift boom shackles, 31x10.5r15 Treadwright Guard Dogs.
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Unread 09-17-2013, 12:40 AM   #7
booboowv77
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I'm running 48's in mine and I get a nice normal 750 rpm and lower with no problems
__________________
GOOGLE IS YOUR FRIEND!!!
Just my toy!
89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
Built not Bought #759
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Unread 09-17-2013, 12:45 AM   #8
c5wagner
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I have a feeling I have a terrible vacuum leak somewhere but I can't find it. I think it's vacuum because the plugs show lean conditions
__________________
Big Red Money Pit: 1989 Base YJ, 4.2l, MC 2150, nv3550, nv241or with 4:1 low, 2003 Rubicon f D44 & r ford 8.8 with 4.10 gearing, Skyjacker 4" double military wrap springs, RC perf. 2.2 shocks, homebrew 1/2" lift boom shackles, 31x10.5r15 Treadwright Guard Dogs.
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Unread 09-17-2013, 12:47 AM   #9
booboowv77
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1989 YJ Wrangler 
 
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spray carb cleaner around the base and see if it changes anything. Alot of people problems at the gasket.
__________________
GOOGLE IS YOUR FRIEND!!!
Just my toy!
89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
Built not Bought #759
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Unread 09-17-2013, 12:50 AM   #10
c5wagner
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1989 YJ Wrangler 
 
Join Date: Sep 2013
Location: Reno, Nevada
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Quote:
Originally Posted by booboowv77 View Post
spray carb cleaner around the base and see if it changes anything. Alot of people problems at the gasket.
I did that already, I checked all mounting surfaces to make sure they're not warped, replaced gaskets and no leaks still. This is the first thing I have been truly lost as what to do with my jeep
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Big Red Money Pit: 1989 Base YJ, 4.2l, MC 2150, nv3550, nv241or with 4:1 low, 2003 Rubicon f D44 & r ford 8.8 with 4.10 gearing, Skyjacker 4" double military wrap springs, RC perf. 2.2 shocks, homebrew 1/2" lift boom shackles, 31x10.5r15 Treadwright Guard Dogs.
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Unread 09-17-2013, 01:03 AM   #11
booboowv77
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I still think something is hold it up, I would double check that first. I have not had this problem but hopefully some one will chime in in the morning that might have other possible solutions.
__________________
GOOGLE IS YOUR FRIEND!!!
Just my toy!
89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
Built not Bought #759
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Unread 09-17-2013, 02:04 AM   #12
c5wagner
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1989 YJ Wrangler 
 
Join Date: Sep 2013
Location: Reno, Nevada
Posts: 68
Quote:
Originally Posted by booboowv77 View Post
I still think something is hold it up, I would double check that first. I have not had this problem but hopefully some one will chime in in the morning that might have other possible solutions.
You were right, I very thoroughly checked all the throttle shaft parts and found a slight bend on the throttle connector causing a bind, it was very hard to see without VERY close inspection.
__________________
Big Red Money Pit: 1989 Base YJ, 4.2l, MC 2150, nv3550, nv241or with 4:1 low, 2003 Rubicon f D44 & r ford 8.8 with 4.10 gearing, Skyjacker 4" double military wrap springs, RC perf. 2.2 shocks, homebrew 1/2" lift boom shackles, 31x10.5r15 Treadwright Guard Dogs.
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