 Carb questions, any guru carb guys? |
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| merrill |
 Aug 12 2005, 03:59 PM
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#1
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Dirt Pimp  Group: Members Posts: 224 Joined: 25-January 05 From: Tahoe City, Ca Member No.: 3,505 Region Association: None  |
My carbed 2.0 is idleing very high (2000-2400) when it warms up (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif) I can tap the throttle and it will drop to 1900, but I would like to adjust it lower. Where do I look for the warm idle adjustment?
It has been popping a bit too, so I got a pertronix that I need to install with the hope that it is points? any feedback is welcome, as well as harassment. |
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Replies(1 - 16)
| lapuwali |
Aug 12 2005, 04:24 PM
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#2
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743  |
Which carb or carbs? Single progressive Weber? Dual IDFs? Dual ICTs? Solexes?
On most carbs, the idle speed is set by the throttle stop, which should be a sprung screw holding the throttle slightly open. On dual carbs, there's one on each, and you need to balance them from side to side (syncing, do a search). There's basically no "cold" idle adjustment, only an idle adjustment. All depends on what we're talking about here. |
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| merrill |
Aug 12 2005, 04:34 PM
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#3
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Dirt Pimp Group: Members Posts: 224 Joined: 25-January 05 From: Tahoe City, Ca Member No.: 3,505 Region Association: None |
Doohhh! Dual carb webber 44 idf.
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| lapuwali |
Aug 12 2005, 04:41 PM
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#4
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
K. Those have throttle stop screws holding the throttle arm slightly open. They're on the outboard side of the carbs, either forward or aft, depending on the linkage you have. Up along the side of one barrel on each carb. You really need to get a synchronizer tool like a Synchrometer to adjust these correctly, so both carbs flow the same at idle. You *can* just turn each one 1/4 turn, wait a bit for the idle to stabilize, and repeat. Turn out to lower idle speed.
They'll idle VERY low when cold when they're set up to idle correctly hot. You'll have to hold the throttle with your foot until it warms up enough to idle properly after a cold start. |
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| merrill |
Aug 12 2005, 04:51 PM
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#5
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Dirt Pimp Group: Members Posts: 224 Joined: 25-January 05 From: Tahoe City, Ca Member No.: 3,505 Region Association: None |
Thanks James (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)
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| rhodyguy |
Aug 12 2005, 09:05 PM
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#6
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,082 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
back one side off pretty well(idle adj screw). then turn the idle down with the other. then readjust the loose one just to the point of the idle increasing again. with the engine off, open the butterflys (with the linkage cross bar) and let it close on it's own. it should snap back with authority. a weak spring sometimes will be overcome by the vaccum and the plates will open a bit. "poping" out the exhaust or "sneezing" back through the carbs?
k |
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| maf914 |
Aug 13 2005, 07:13 AM
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#7
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Not a Guru! Group: Members Posts: 3,049 Joined: 30-April 03 From: Central Florida Member No.: 632 Region Association: None 
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If you don't have a Weber manual, I'd recommend the Haynes Weber book. It covers most of the various Weber carbs and has tuning and rebuilding procedures for each. If the carbs are in good shape, tuning is really not difficult. A good linkage system is also important, with everything smooth and tight, i.e. no slop in the motion. Get a synchronizing tool and all of the things suggested above will become obvious.
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| merrill |
Aug 13 2005, 11:31 AM
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#8
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Dirt Pimp Group: Members Posts: 224 Joined: 25-January 05 From: Tahoe City, Ca Member No.: 3,505 Region Association: None |
Rhody Guy, I am not sure about the sneezing. I seems that it is more of a pop or ping than sneeze. It does sound as if it is at the carbs though.?
Itis funny that I understand FI really well and I buy a carbed car (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) I will order the haynes manual. |
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| r_towle |
Aug 13 2005, 12:55 PM
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#9
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Custom Member Group: Members Posts: 24,584 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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check your valve adjustments. poorly adjusted valves can cause it to backfire out the intake.
Next Pull the four main jets (screwed in from the top, in the middle you will see two large flat head brass screw heads.) you may need to take off the air cleaner base, may not...that depends on the base plate manufacturer. Pull out the tube, its about 1.2 inches long. The main jet is at the bottom, press fit in. On that jet should be a size number (its really small) Make sure they are all the same. Second, look down the venturis, the large 36 mm hole the air goes down. Each one is marked with 36mm or 38mm and so on. Once you have confirmed that all is the same, check back here with those numbers. You could have a poorly configured setup for that engine and you might need to change those parts. Also, when is it backfiring....upon accel or decel?? Rich |
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| BGman |
Aug 13 2005, 01:12 PM
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#10
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Greg Group: Members Posts: 87 Joined: 18-January 04 From: Owensboro, KY Member No.: 1,575 Region Association: None |
Merrill, don't mean to hijack your thread...
Rich- Mine ocassionally backfires during deceleration (especially when I have run the revs really high and let off)...but only until the engine temps are up. After the engine really gets warmed up- it doesn't seem to happen. What does this mean to you? (dual 44's on a 2270) |
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| r_towle |
Aug 13 2005, 01:17 PM
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#11
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Custom Member Group: Members Posts: 24,584 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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what size mains, what size venturis???
Rich |
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| merrill |
Aug 13 2005, 05:13 PM
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#12
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Dirt Pimp Group: Members Posts: 224 Joined: 25-January 05 From: Tahoe City, Ca Member No.: 3,505 Region Association: None |
Thanks for the feedback Rich. I will not be able to get to that for a day or two. I will try to post pics with #s.
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| r_towle |
Aug 13 2005, 05:24 PM
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#13
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Custom Member Group: Members Posts: 24,584 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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most of these weber carbs have no choke circuit. My advice is DO NOT rev the car till its warmed up. Its not good for the rest of the motor, and you are running to rich. Rich |
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| SirAndy |
Aug 13 2005, 05:38 PM
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#14
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Resident German Group: Admin Posts: 41,658 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
i'm not rich, but i do have an opinion ... (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) what cam? what overlap on the cam? what kind of exhaust and muffler? my 2056 does that too and all kinds of adjustment on the carbs and valves can not dial it out completely. on my car, i believe it's due to the high overlap cam combined with the (pretty restrictive) stock HE and exhaust ... (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) Andy |
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| r_towle |
Aug 13 2005, 05:44 PM
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#15
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Custom Member Group: Members Posts: 24,584 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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I was successful at tuning it out of a beetle with alot of advice from Aircooled Technologies...
I ended up with several sized vents and several jets,,,,but I am sure it can be dialed in.... Those guys even have a spreadsheet of valid setups with bore,stroke and cam...it was alot of trial and error (alot of error) but they made me some custom vents in between the stock sizes and that did the trick. Rich |
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| BGman |
Aug 13 2005, 09:34 PM
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#16
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Greg Group: Members Posts: 87 Joined: 18-January 04 From: Owensboro, KY Member No.: 1,575 Region Association: None |
Don't know about cam specs- but I do have an older 4 into 1 header/exhaust system....this may be just the excuse I need to convince the wife that I need a new one!
Really, it is not much of a problem. You are right, if I just take it easy for the first 5-7 minutes of the trip everything is aok. |
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| IronHillRestorations |
Aug 14 2005, 10:46 AM
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#17
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I. I. R. C. Group: Members Posts: 6,722 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None
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Is this a new engine? Did it just develop this problem?
Make sure you don't have a problem with the throttle cable or pedal sticking. Make sure the igntion is properly timed, and that the distributor is advancing with engine speed and retarding when you back off. A stuck advance plate can cause the problems you are having. Go back to square one. Make sure the valves are correctly adjusted (stone cold). Make sure the ignition timing is dead on. Make sure you've got the correct jet and venturi set up for your engine. |
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