weber carb replacement
- Thread starter jakec
- Start date
superj
Active member
Wow, do you know anything about carbs? Weber is a higher end carb then holley and carter. Carter is above holley. Rochester is above carter and holley but not much above carter as carter and rochester are both good carbs.
Holley is the bottom of the barrel when it comes to carbs. Back in the day they were wll known as the leakey carbs. Webers willgive you trouble if everything is not tuned but once you have your other stuff together, the weber is way more dependable then holley.
I would say you have a vacuum leak if its giving you trouble below 2k rpms but is fine above that. It sounds like that is your issue because when the butterflies are open for more then 2k rpm, you vare getting a closer to correct mixer where as below 2k rpm, you are way to lean.
Also, I keep hearing of people running a 32/36 on their 4.2 but even bmw guys run a weber 38 on anything over a 2.0 4 cylinder. I had a 32/36 on my 1.8 and wanted to upgrade. It ran great but felt like it needed more juice. Try a 34 like lots of people use, if you want but I have one and am really thinking of moving to a 38 because the 4.2 seems like the 34 is choking it up.
Holley is the bottom of the barrel when it comes to carbs. Back in the day they were wll known as the leakey carbs. Webers willgive you trouble if everything is not tuned but once you have your other stuff together, the weber is way more dependable then holley.
I would say you have a vacuum leak if its giving you trouble below 2k rpms but is fine above that. It sounds like that is your issue because when the butterflies are open for more then 2k rpm, you vare getting a closer to correct mixer where as below 2k rpm, you are way to lean.
Also, I keep hearing of people running a 32/36 on their 4.2 but even bmw guys run a weber 38 on anything over a 2.0 4 cylinder. I had a 32/36 on my 1.8 and wanted to upgrade. It ran great but felt like it needed more juice. Try a 34 like lots of people use, if you want but I have one and am really thinking of moving to a 38 because the 4.2 seems like the 34 is choking it up.
superj
Active member
I wasn't asking it to you, sorry on that.
Holley is not junk, they have their place on hot rods. And they have probably worked on their bowl leak issues over the years because they are still here. If they hadn't they probably would've went out of business. They just aren't good for use on everything, especially on jeeps. (Unless they make a pressurized bowl now for off-roading. Last I had heard, only rochester and one of the newer carb companies made those but I have not been (really) in and up on carbs for a while.
Yes, the first paragraph I had put up earlier bothered me because I was afraid it might be offensive because its hard to explain stuff with no body language and tone in writing. Sorry about that
Holley is not junk, they have their place on hot rods. And they have probably worked on their bowl leak issues over the years because they are still here. If they hadn't they probably would've went out of business. They just aren't good for use on everything, especially on jeeps. (Unless they make a pressurized bowl now for off-roading. Last I had heard, only rochester and one of the newer carb companies made those but I have not been (really) in and up on carbs for a while.
Yes, the first paragraph I had put up earlier bothered me because I was afraid it might be offensive because its hard to explain stuff with no body language and tone in writing. Sorry about that
jakec
New member
no i dont know that much about carbs but i do know the 3 ford 4x4s i have had with holleys ran great and i could adjust em and work on em a little bit. that damn weber i cant do anything to it to make any kind of difference in how it runs. maybe im just a little more familiar with a holley. thats why i was asking. thanks for the help. thats a sweet nova too buck hour!
superj
Active member
CARBURETOR SET UP AND LEAN BEST IDLE ADJUSTMENT
i hate trying to be on a forum at work because of the security system blocking the responses.
i didn;t meant to sound abrasive, i always forget that younger guys don't have much carb experience because they were all phased out prior to you guys vehicles.
i hate trying to be on a forum at work because of the security system blocking the responses.
i didn;t meant to sound abrasive, i always forget that younger guys don't have much carb experience because they were all phased out prior to you guys vehicles.
Buck hour
New member
superj said:
The jet and the truck are upstate at a cabin. Yep its a 150 built on a 350 chassis 8" lift 44 super swampers 31/4 straight pipes that lead to glass packs. Dana 60 rear and Dana 40 up front. The whole truck at every frame junction has been reinforced. Bell c-4 transmission. She weighs about 9000lbs and I can take a eclipse turbo spider off the line untill I get to 65. Then I have ti back off. She's geared way to low to do any high end speeds. Oh and she's purple! We call her the people eater
GuidosCrawler
New member
My carb guy says that a 36 is ideal for the 4.2 unless your running a performance header then you should upgrade to a 38. But he swears by weber carbs says he run them all and ended up right back at weber!
jakec
New member
it didnt sound abrasive to me, i dont know much about em thats why i ask yall. i think i have a leak between one of the adapter plates between the intake and the carb and i think i also have a bad choke. im gonna fix that and then see how the weber runs. everybody says theyre great carbs.
superj
Active member
that is badass!!!! you have it built for off roading with a freaking cobrajet motor. that is sweet. people always blow off those big trucks thinking they are slow but the gearing in them make them killer vehicles for light to light drag racing.
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My carb guy says that a 36 is ideal for the 4.2 unless your running a performance header then you should upgrade to a 38. But he swears by weber carbs says he run them all and ended up right back at weber.
i have heard that also but running this 34 and having had other weber carbs on smaller engines, i just feel like i would be happier with a 38. i don't know, it might just be because the 34 is a progressive carb, like a 32/36 is (progressive means the primary throttle plate opens before the secondary, to save fuel.) the 38 is a synchronous carb meaning which means both plates open at the same time. eats a little more fuel but you get full power as soon as you move your foot. on a progressive, if you are accelerating, the primary only opens until you get to certain point on the linkage where the secondary plate opens and then you get this feeling of more power because now you have two throats feeding the cylinders. but with a 32/36 and a 34/34, the total opening measurement is still only 68 at full throttle where as a 38/38 is 76 millimeters of open space for the air to enter through. i know alot of 4x4 guys are not interested intop end but i like to be able to pass on the highway and get out of the way of oncoming traffic, if i need to. right now, i don't feel like the jeep can do it. my wife's fuel injected 93 4.0 wrangler will smoke the tires from a stop. i want mine to do that also so i will try the 38 sometime and see if that is closer to what i want.
i do agree that weber carbs are some of the best though. i have been through a number of different types and for what i do, they are.
now on a hot rod, holley, carter, and rochester will all act equally but for other applications, you have to go by what you are doing to decide on the best. the k5 blazers came with a quadrajet 4 barrel, if i remember right. they were made for 4x4ing also. the quadrajet has a horrible rap because no one liked tuning them but they are an excellent carb and worked great for what htey were made to do, run a stock chevy v8 and 4x4. the bowl doesn't drain on those, like our webers and the other aftermarket jeep carbs. you get on a steep hill and your going to run out of gas with an aftermarket jeep carb because the bowl will drain out of the little hole in the top (the tiny one by the choke butterfly) quadrajets don't have the bowl. quadrajets were made by holley, rochester, and carter during the run that chevy used them so you can have one by any of hte major american carb makers but you can tell who made each one when they get old because of the problems they will give you.
the good thing about american carb makers is they were a little sloppy in their castings so you could take the carb apart (for a rebuild) and while its apart, you can get a little file and smooth some of the cast marks off and round some sharer edges and gain some cfm for a little hidden power. i tried this on a weber and it didn't work, it more screwed the carb up then helped it any but it could've been me but. onto the original part of this paragraph. there are certain carbs for certain applications and each one will be better then the other, depending on what you are doing. i happen to be a fan of webers (from my bmw racing days) and solex from my aircooled vw days because of how dang dependable those stock carbs were. i had a holley bugspray and it was a piece of junk so i went to a weber and it was ok but i ended up going back to the solex after a while. the bug sprays are known for being bad and the weber just wasn't good for that application.
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you think the choke is bad or is it just out of adjustment? tomorrow morning, open the hood and pop the top of the air cleaner off and make sure the top plates are closed all the way. yours are square, right? they should be fully closed on a cold engine.
this should not be how your carb is on a cold day. this is fully open chokes. see the plastic thing on the right side of the carb, in the pic. it has a ring around itwith three screws, roughly 120* apart? that is the adjustment for your choke plates. if you pop the hood and those plates are any near open, loosen the three screws around that plastic thing and twist the plastic thing until you close the choke plates. close the but don't go past where they close too much or they will not open all the way when they are warm. once you close them, tighten the screws back up and see if your jeep starts up.
to tighten the leak between the adapter plates, remove the nuts at the base of the carb
you will probably have to unhook the throttle cable and some vacuum lines so make sure and mark them or put it back together fairly quickly so you remember where they go. either way, under the carb, if you have two plates stacked on top of each other, there should be a gasket between the two that might need some rtv or need replacing. the one under the bottom plate might need rtv or replacing also, same as the one on the bottom of the carb but no rtv on that one. stuff comes loose after a bit so its good to check those if you think you have a leak there.
you're heading the right direction to get it running right, so keep going and asking questions for whatever you need. (all those carb pics are from my weber 32/36 on the ol' 1.8 litre bmw engine in my 81 bmw 320i i used to have)
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