Its Alive!!!! now I got a carb question

91GTA350 · 05-31-2005, 12:21 AM

Well after countless hours getting parts and laying on the ground working on the jeep. I got my $300 89 Jeep working. Of course I have atleast $400 in parts in it so far, with $600 more coming on Thursday. So when I pulled the carb and opened it up, my "carb expert" said "its looks a lot cleaner than the ones I work with, so I would not rebuild it." I spent the better half of today trying to figure out why the bowls wouldn't fill up. I found out that the needle was stuck and it didn;t matter where the float was, the needle was always closed. I think I might need to rebuild now.

So on to the question. I am told the proper name is the venturis, or the little holes where the fuel sprays from when the throttle is pressed. When at idle, I can't see any fuel coming out of them. I think this is correct. When the throttle is held at say 1500 to 2000 RPMs, I can see a steady stream coming out of the one on the passenger side, but the drivers side is still dry as a bone. Is this suposed to be this way, or are the passages clogged? If I pull the throttle quickly for a hard fast rev, both sides squirt fuel forcefully. Is this how a carb is suposed to function or is mine in desperate need of some TLC.

Thanks for any help,
Steve

dcafaro · 05-31-2005, 06:23 PM

You should have even flow coming out of both of the venturi tubes. Some drill them slightly larger to limit clogging other just clean them with a good carb cleaning. Either way you need to pull apart the top part of the carb where the axis is for the butterfly or detatch some linkage and remove the upper half of the carbto get the cluster out. Word of advice have a lone magnetic pick up tool handy if you do it on the vehicle. Neither is much easier than the other. I would remove the whole thing and spend the 20.00 and rebuild it yourself.

91GTA350 · 05-31-2005, 11:05 PM

Ok so I have the rebuild kit now. I am nervous of doing the job because the instructions (yes, i read them before screwing up for once) say that I have to measure a few things. I forget what they are and the sheet isn't handy right now. It tells me measurements like 31/64" and 9/32". I have a tape measure that goes to 1/16". If I know that the carb works, is there any reason that I can't just open the carb up and replace everything that I get new in the kit. Do I have to make these tight measurements, and with what would I use to do the measureing?

Thanks for all help.

Steve

dcafaro · 06-01-2005, 05:34 PM

I did just that, I didn't do any measuring. Just check the clip where the float is and make sure that it isn't bent so far forward that the float doesn't float, other than that just replace the gaskets springs and little metal ball in each chamber of the carb.

91GTA350 · 06-03-2005, 12:21 AM

Good to hear that. I have bought too many tools this summer to have to get a micrometer for a few measurements.

Thanks

Steve

vaughn.smithjr · 06-05-2005, 03:31 PM

Ok im gonna try to explain this so bear with me.. The idle circuit of a carburetor is not the same as the primary or secondary systems of a carb, sometimes the primary may incorporate the idle circuit in it but not always, when you give the pedal a goose the primary "jets" will pump fuel into the intake when you stomp on it withe aide of some kind of help from usually an accelerator pump the secondary jets will kick in with the primarys already working. For specific operation youd need a manual for your carb and the specific model. Usually when i rebuilt a carb i try not to disturb anything during disassembly, if there is a problem youll be more apt to find it. Usually when you measure something its the level of the float in the bowl. This is done with a ruler, and some patience, after all we are talking about something thats about as thick as your fingernail. If the bowl isnt filling up the needle may be stuck, have you done a pressure test, approx 5-12 psi should do it, again consult the manual, Maybe the seat on the needle is junk or the float is bad.... Clean it good, make sure to use carb cleaner so you dont leave a residue that can lead to frustrating late nights. Try tapping on the bowl housing of the carb to see if you can maybe get the float to jiggle or get unstuck if it is, use the handle of a screw driver.... Hope ive helped a little

05-31-2005, 11:05 PM	#3
91GTA350 Registered User Join Date: Mar 2005 Location: Purdue Posts: 329 Profile Gallery Classifieds My Jeeps	Ok so I have the rebuild kit now. I am nervous of doing the job because the instructions (yes, i read them before screwing up for once) say that I have to measure a few things. I forget what they are and the sheet isn't handy right now. It tells me measurements like 31/64" and 9/32". I have a tape measure that goes to 1/16". If I know that the carb works, is there any reason that I can't just open the carb up and replace everything that I get new in the kit. Do I have to make these tight measurements, and with what would I use to do the measureing? Thanks for all help. Steve __________________ -89 sahara 258: [U]HAD[/U] a peugot and a d35 5/15/05 - took ownership and started money pit 9/17/05 - found a 3.5' deep water hole 2/18/06 - destroyed spiders in d35 4.2/AX-15/NP-231/SYE/30/8.8/3.55/RE 2.5"/31"

06-03-2005, 12:21 AM	#5
91GTA350 Registered User Join Date: Mar 2005 Location: Purdue Posts: 329 Profile Gallery Classifieds My Jeeps	Good to hear that. I have bought too many tools this summer to have to get a micrometer for a few measurements. Thanks Steve __________________ -89 sahara 258: [U]HAD[/U] a peugot and a d35 5/15/05 - took ownership and started money pit 9/17/05 - found a 3.5' deep water hole 2/18/06 - destroyed spiders in d35 4.2/AX-15/NP-231/SYE/30/8.8/3.55/RE 2.5"/31"

05-31-2005, 06:23 PM	#2
dcafaro Registered User Join Date: Dec 2003 Posts: 771 Profile Gallery Classifieds My Jeeps	You should have even flow coming out of both of the venturi tubes. Some drill them slightly larger to limit clogging other just clean them with a good carb cleaning. Either way you need to pull apart the top part of the carb where the axis is for the butterfly or detatch some linkage and remove the upper half of the carbto get the cluster out. Word of advice have a lone magnetic pick up tool handy if you do it on the vehicle. Neither is much easier than the other. I would remove the whole thing and spend the 20.00 and rebuild it yourself.

06-01-2005, 05:34 PM	#4
dcafaro Registered User Join Date: Dec 2003 Posts: 771 Profile Gallery Classifieds My Jeeps	I did just that, I didn't do any measuring. Just check the clip where the float is and make sure that it isn't bent so far forward that the float doesn't float, other than that just replace the gaskets springs and little metal ball in each chamber of the carb.

06-05-2005, 03:31 PM	#6
vaughn.smithjr Registered User Join Date: Aug 2004 Location: stationed in TX Posts: 28 Profile Gallery Classifieds My Jeeps	Ok im gonna try to explain this so bear with me.. The idle circuit of a carburetor is not the same as the primary or secondary systems of a carb, sometimes the primary may incorporate the idle circuit in it but not always, when you give the pedal a goose the primary "jets" will pump fuel into the intake when you stomp on it withe aide of some kind of help from usually an accelerator pump the secondary jets will kick in with the primarys already working. For specific operation youd need a manual for your carb and the specific model. Usually when i rebuilt a carb i try not to disturb anything during disassembly, if there is a problem youll be more apt to find it. Usually when you measure something its the level of the float in the bowl. This is done with a ruler, and some patience, after all we are talking about something thats about as thick as your fingernail. If the bowl isnt filling up the needle may be stuck, have you done a pressure test, approx 5-12 psi should do it, again consult the manual, Maybe the seat on the needle is junk or the float is bad.... Clean it good, make sure to use carb cleaner so you dont leave a residue that can lead to frustrating late nights. Try tapping on the bowl housing of the carb to see if you can maybe get the float to jiggle or get unstuck if it is, use the handle of a screw driver.... Hope ive helped a little