International Full Size Jeep Association
Home Forums Reader's Rigs Tech Library Trail Stories FSJ-List
International Full Size Jeep Association  

Go Back   International Full Size Jeep Association > Tech Archives > Engine

Reply
 
Thread Tools Display Modes
  #21  
Old 08-19-2008, 12:51 AM
Keman's Avatar
Keman Keman is offline
Member
 
Join Date: Jul 22, 2008
Location: Seattle, Wa
Posts: 207
Quote:
Originally Posted by wickedwagon767
I'm trying to decide wether or not I need to rebuild my MC 4350. I just bought the '78 Cherokee. It had to have a liberal spraying of started fluid and several attempts over a 20 minute period to get it started when I went to pick it up. Once it cranked it ran great. Cruised between 70 and 80 all the way home, about 35 miles.

I've been told the floats "get stuck" when older carbs sit for a while without being run. This one was a daily driver for a year, then was started periodically over six months until I bought it.

Any leads?

Is it one with a float level view hole? Should be a bolt or screw on the side of the bowls. If it is, open the view hole and spray carb cleaner into the float bowl. That may clean enough gunk to release it.. Otherwise, get gaskets and pop off the float bowls and clean them manually. way less that a full rebuild, and should take less than a half hour.

My 2300 had just the opposite issue, the float stuck in the open position and poured gas out the top vent. I did a complete rebuild due to the 41 year age and unknown maintanence history.
__________________
You might worry less about what most people think, if you understood how rarely they do.

67 Kaiser J3000, 327 vigilante, D44/D53, less than average rust. Currently "asthetically challenged"

05 TJ, wheelin rig.
Reply With Quote
  #22  
Old 08-19-2008, 01:32 AM
wickedwagon767's Avatar
wickedwagon767 wickedwagon767 is offline
Bleedin' Gasoline
 
Join Date: Dec 26, 2005
Location: DFW
Posts: 1,932
Quote:
Originally Posted by Keman
Is it one with a float level view hole? Should be a bolt or screw on the side of the bowls. If it is, open the view hole and spray carb cleaner into the float bowl. That may clean enough gunk to release it.. Otherwise, get gaskets and pop off the float bowls and clean them manually. way less that a full rebuild, and should take less than a half hour.

My 2300 had just the opposite issue, the float stuck in the open position and poured gas out the top vent. I did a complete rebuild due to the 41 year age and unknown maintanence history.


I'll take a closer look for a view hole
Reply With Quote
  #23  
Old 10-26-2008, 10:46 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
2100 Series
6RHA2 Model

Seems to be leaking from the accelerator pump, possibly the diaphram. Would the diaphram be an easy fix ? Is this a good carb? Jeep runs good but takes a lot of pumps to get initial start.
Reply With Quote
  #24  
Old 10-27-2008, 04:54 AM
Lindel's Avatar
Lindel Lindel is offline
Perfesser of Jeepology
 
Join Date: Jun 15, 2000
Location: Carpentersville, IL 60110
Posts: 9,204
You'll probably have to buy a complete kit to get the diaphram, but it's an easy fix on the 2150. It's on the front of the carb, and at worst it's messy. Don't do with the engine hot.

2150 is an excellent carb, especially for off-road. It's down side is that it's not very big (only around 350 cfm), and the top can warp fairly easily.
__________________
Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231


Quote:
“Freedom is never more than one generation away from extinction” by Ronald Reagan.


Formerly of DFW/Gun Barrel City, TX - eventually to return...
Reply With Quote
  #25  
Old 10-29-2008, 11:32 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
Quote:
Originally Posted by Lindel
You'll probably have to buy a complete kit to get the diaphram, but it's an easy fix on the 2150. It's on the front of the carb, and at worst it's messy. Don't do with the engine hot.

2150 is an excellent carb, especially for off-road. It's down side is that it's not very big (only around 350 cfm), and the top can warp fairly easily.

My carb is a 2100 series. I replaced the diaphram but I broke one of the bolts from over tightning!!!! GRRRRRR! Its not leaking now but just knowing that it is only being held by the three bolts is driving me crazy ! I tried needle nose pliers but it can't get a grip to remove it. What should I do?
Reply With Quote
  #26  
Old 10-30-2008, 04:51 AM
Lindel's Avatar
Lindel Lindel is offline
Perfesser of Jeepology
 
Join Date: Jun 15, 2000
Location: Carpentersville, IL 60110
Posts: 9,204
You could try vise grips, or if there's a carb rebuilder near you then give them a try.

Is there enough to get a pair of vise grips on them?
__________________
Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231


Quote:
“Freedom is never more than one generation away from extinction” by Ronald Reagan.


Formerly of DFW/Gun Barrel City, TX - eventually to return...
Reply With Quote
  #27  
Old 10-30-2008, 05:34 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
Quote:
Originally Posted by Lindel
You could try vise grips, or if there's a carb rebuilder near you then give them a try.

Is there enough to get a pair of vise grips on them?

Negative. It is super cold up here and I should have done this job in a warm garage. SNAP! GRRR! I have a punch list of things that need to be accomplished before she is road worthy. The carb rebuild is one of them and I'm sure that they could pull it out, hopefully. I don't even know is this carb is functioning correctly and if all parts are even there to begin with. The Jeep does start though so thats good.

A drive around the block and I can only top her out at about 25mph. I'm missing the driver side exhaust manifold down pipe. Could no back pressure do this?
Reply With Quote
  #28  
Old 10-30-2008, 08:15 PM
chrisnsarah's Avatar
chrisnsarah chrisnsarah is offline
FSJ Maniac
 
Join Date: Sep 24, 2000
Location: Nampa, ID
Posts: 3,282
Holley 2300 adjustments

I am curious to know when the accelerator pump arm is supposed to start moving on this carb. Is it supposed to be at the same time the throttle starts to open.

When you start out in gear or jab the accelerator quickly, it will spit or miss, then idle fine or run fine once you get moving.

I noticed the pump arm doesn't move until the throttle is partially opened. I have a spare Holley and the arm moves immediately when the throttle is moved.

There is no mention of an adjustment in the manual. Is it ust trial and error until I find a good spot? I overhauled this carb during the summer.
__________________
'64 J200 thriftside
'67 J2000 townside custom cab
'68 Jeepster Commando
'69 Super Wagoneer
'75 J10
'79 Cherokee S WT
'75 Cherokee
'61 Aristocrat Lil Loafer
Reply With Quote
  #29  
Old 10-30-2008, 08:35 PM
Lindel's Avatar
Lindel Lindel is offline
Perfesser of Jeepology
 
Join Date: Jun 15, 2000
Location: Carpentersville, IL 60110
Posts: 9,204
Chris, I've always adjusted the accel pump (on a Holley) so that I can blip the throttle (in park) and it doesn't stumble or hesitate. It's always worked for me.

If you go to Holley's website, you should be able to find the initial tune up for installing it. That has all the adjustments you need to do out of the box.

AMC, on yours I don't think that back pressure (or lack of) would be your problem. It's most likely carb related, and probably a choke adjustment. It may very well be a vacuum leak, these monsters are prone to that. Look to see if the PCV hose has come off the back of the carb. If it's not vacuum, look at the choke.
__________________
Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231


Quote:
“Freedom is never more than one generation away from extinction” by Ronald Reagan.


Formerly of DFW/Gun Barrel City, TX - eventually to return...
Reply With Quote
  #30  
Old 10-30-2008, 08:47 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
Quote:
Originally Posted by Lindel
Chris, I've always adjusted the accel pump (on a Holley) so that I can blip the throttle (in park) and it doesn't stumble or hesitate. It's always worked for me.

If you go to Holley's website, you should be able to find the initial tune up for installing it. That has all the adjustments you need to do out of the box.

AMC, on yours I don't think that back pressure (or lack of) would be your problem. It's most likely carb related, and probably a choke adjustment. It may very well be a vacuum leak, these monsters are prone to that. Look to see if the PCV hose has come off the back of the carb. If it's not vacuum, look at the choke.

Thanks Lindel ---

I'll check around the carb.

I've ordered a Haines manual and hopefully it will help me. Other people I spoke too also concluded that the down pipe should not make a difference. My carb is probably way out of wack. Should the butterfly valve flap open/closed when throttling? If so mine does not.......

Again I would like to get it rebuilt but I'm just trying to get the Jeep to run as best as possible with little $ down. Just to see what I have and go from there.
Reply With Quote
  #31  
Old 10-31-2008, 04:42 AM
Lindel's Avatar
Lindel Lindel is offline
Perfesser of Jeepology
 
Join Date: Jun 15, 2000
Location: Carpentersville, IL 60110
Posts: 9,204
If you're talking about the flat metal at the top of the carb, that's the choke. This time of year it should be nearly closed when you start the engine, and slowly open as the engine warms up. If it's not opening up, then that could be part of your problem, not enough air available to the engine.
__________________
Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231


Quote:
“Freedom is never more than one generation away from extinction” by Ronald Reagan.


Formerly of DFW/Gun Barrel City, TX - eventually to return...
Reply With Quote
  #32  
Old 11-03-2008, 06:00 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
Choke valve is open and I believe that a part of my problem might be a bad fuel pump. I have to give a few shots of gas to the carb before initial start. I'm going to change out the fuel pump and see what happends. I called a local carb guy and thinks this would be my problem. Keeping my fingers crossed!
Reply With Quote
  #33  
Old 11-03-2008, 10:47 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
Maybe my fuel filter needs to be replaced.... I'll try that first.
Reply With Quote
  #34  
Old 11-05-2008, 01:14 PM
jeepbob jeepbob is offline
Jeep Idiot
 
Join Date: Jan 16, 2001
Location: Caro, Mi, USA
Posts: 2,513
I just bought a Generic bolt on holley with no external float adjustment tossed it on and just adjusted the idle jets and speeds (high and low speed Idle) and it was good to go. I do run a pressure regulator at 3.5 lbs.
__________________
65 wag. with a bunch of stuff done and more happening.<br /><br />\"If the local junkyard calls you for Jeep parts, you might be a redneck\".... and yes they do!
Reply With Quote
  #35  
Old 11-09-2008, 07:52 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
I replaced both fuel pump and filter. Better initial starts but still only moves to 25mph with a high rpm. I checked around the carb and all hoses seem to be intact. The manifold (vent?) hose behind the carb has been plugged. Replace carb? Bad timing? Bah...........
Reply With Quote
  #36  
Old 11-10-2008, 10:38 PM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
What are your guys thought on maybe a bad transmission modulator? When the Jeep wants to switch to second gear it hesitates (briefly) as if it does not know what to do. Engine idle is good. I'm still wondering if maybe the missing down pipe from exhaust manifold is still in play.
Reply With Quote
  #37  
Old 11-11-2008, 07:04 AM
Lindel's Avatar
Lindel Lindel is offline
Perfesser of Jeepology
 
Join Date: Jun 15, 2000
Location: Carpentersville, IL 60110
Posts: 9,204
I was thinking along those lines, not modulator specifically, but tranny related.

I don't thing your exhaust is an engine issue at this point.
__________________
Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231


Quote:
“Freedom is never more than one generation away from extinction” by Ronald Reagan.


Formerly of DFW/Gun Barrel City, TX - eventually to return...
Reply With Quote
  #38  
Old 11-12-2008, 12:02 AM
AMC4ME's Avatar
AMC4ME AMC4ME is offline
Member
 
Join Date: Oct 15, 2008
Location: Alaska
Posts: 92
I've been glancing thru the Haines manual lately and I'm trying to come up with different solutions to the problem. This not the original engine ( I believe) and it was not quite honed in. Now I'm guessing on throttle control linkage with the tranny. Perhaps the linkage has too much slack?.

Sorry all ----- I really don't mean to clutter up this forum with my particular Jeep issue. I don't have any one to physicaly help me on my Jeep and I'm learning as I go.
Reply With Quote
  #39  
Old 11-12-2008, 09:53 AM
Lindel's Avatar
Lindel Lindel is offline
Perfesser of Jeepology
 
Join Date: Jun 15, 2000
Location: Carpentersville, IL 60110
Posts: 9,204
Don't sweat it, that's what we're here for.
__________________
Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231


Quote:
“Freedom is never more than one generation away from extinction” by Ronald Reagan.


Formerly of DFW/Gun Barrel City, TX - eventually to return...
Reply With Quote
  #40  
Old 02-01-2009, 11:36 AM
Peter Matusov Peter Matusov is offline
Grease Monkey
 
Join Date: Nov 03, 2002
Location: San Diego, CA
Posts: 446
QJet on a BUick 350

Thanks for the link to the article on the Quadrajet.

I've swapped the QJet that came with the 72 Buick 350 (that was definitely leaning out close to WOT) with a known-good Chevy QJet. It idles well, runs well, and I should be all over it - but starting the truck became a matter of probability and full battery charge! One tap of the foot in the inopportune moment, and it'll flood the engine.

I wish I could make one good carb out of these two...
__________________
Peter Matusov /68 Wag/95 Range Rovers - SWB & LWB/96 Discovery - white and green/01 XC70
AK6PM
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:16 AM.


Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
corner corner