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Old 04-01-2012, 10:52 PM   #1
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4.2 acceleration lag

im trying to figure out whats wrong with my jeep, i have a 4.2 with a webber carb and when i give it throttle in first theres no problem, second gear if i punch it it will bog and want to stall same with the rest. also if i gradually go up to speed and the fully accellerate it does have the lag as much??? i need some help

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Old 04-02-2012, 07:50 AM   #2
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What size tires & gear ratio do you have?

Bigger tires w/ stock gears don't accelerate well.

Likewise w/ shifting too low. If you shift into 3rd at 1000rpms, it's gonna bog a bit.

The carb might possibly be running a bit lean due to jetting or fuel flow (bad pump, clogged filter, etc).

What do your sparkplugs look like? They should be a light/medium tan on the 'white' part near the tip. IF they are much lighter, or darker, you have an air/fuel ratio that's out of whack.

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Old 04-03-2012, 01:41 PM   #3
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It has 31 1050 15 not sure of the gear ratio, but the spark plugs were just replaced and ill have to check the colors. The carb was just cleaned and seemed to work better but still bogs. In second and wants to stall even at switching gears at high rpms, the problems only is in second gear and up. Also I installed a 1 inch transfer case drop and now reverse pops out is that due to the drop kit?
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Old 04-03-2012, 02:23 PM   #4
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Quote:
Originally Posted by kdelbert90
It has 31 1050 15 not sure of the gear ratio, but the spark plugs were just replaced and ill have to check the colors. The carb was just cleaned and seemed to work better but still bogs. In second and wants to stall even at switching gears at high rpms, the problems only is in second gear and up. Also I installed a 1 inch transfer case drop and now reverse pops out is that due to the drop kit?
Yes the t case drop does do thar gotta trim the floor out a little and get in ur Jeep get it warm take outta gear and punch it see if it reacts well or slow to react or almost die
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Old 04-03-2012, 03:33 PM   #5
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Well. even Weber/Redline say their carbs sometimes need to be recalibrated to perform really well. Escpecially if your jeep deviates from stock (headers, etc)

Here's a link that mentions a jeep jet kit at the bottom.

Making The Right Choice 32 or 36

It would really help to know WHICH weber carb you have to make any suggestions. There are different types/sizes suited to different engines.

The 32/26 is most popular for stock 4.2 motors. Then there are larger ones that are more suited for hot-rodded mills.

Assuming your ignition timing is okay, and that you have the 32/36 carb...your issues are probably one/or combo of these:

1) Fuel pressure/Float level. Specific to each type carb. IF you idle/accelerate in 1st well....I'd say you're probably ok here.

2) Progressive feature is opening the secondary circuit too soon. You could probably google this info and find it thru Redline (weber carb guys). There are a lot of tuning links on their website.

3) Wrong sized jets for your particular application. I'd do a search for "4.2 weber jets" & see what other guys w/ your combo are running. Where you live (altitude) can play a big part in getting a carb jetted correctly.

The good news is, it's just a tuning problem & won't take much $$$ to correct....you just have to diagnose it correctly.
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Old 04-03-2012, 09:17 PM   #6
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Check the accelerator pump.
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Old 04-03-2012, 09:31 PM   #7
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Quote:
Originally Posted by Nubby55
Check the accelerator pump.
Exactly what I was attempting to get him to check
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Old 04-03-2012, 09:54 PM   #8
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and, your time being off can affect a weber more then a normal carb, especially on a 32/36. so basically, check everything
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Old 04-05-2012, 12:03 AM   #9
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Thanks guys, I'm currently in paramedic school so the only Time I mess with it is on the weekends,and that's if I don't have plans, ill be sure to let you all know the outcomes

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