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> Correct fuel pressure for dual carbs?
terrymason
post May 16 2007, 11:16 PM
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I'm having alittle trouble getting my dual carbs dialed in, the 1st is rich, and the second is lean. My fuel pump was putting out 3.5psi, but the guy I bought my carbs from said I should run 2.6psi instead. What do you guys think?

I've got 60 idle jets and 180 mains, which I thought was overkill, until he told me that I should run 2.6 instead of 3.5 psi.
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rhodyguy
post May 17 2007, 09:35 AM
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any other symptoms? snapping/popping back thru the carbs as you open the throttle plates? back fire on decel? my first thought is you've got the droplinks misadjusted if the timing and valve adjments are correct. one droplink longer than the other creating a condition where one carb is 'ahead' of the other. the one "ahead' might be set correctly and the other carb is running lean. don't use the idle speed adj screws to try and correct this condition. it won't work. tearing your carbs apart is the last step when all else fails. get out the cb weber tech book and what ever syncro tool you have, go to the pre dial in settings (the cb book is pretty clear on how this is done), with 1 (leave the other alone for now) idle speed adj screw turn the idle up to about 2k and measure the flow on the front venturis on both carbs. if the flow indicated is equal, go to the troubleshooting guide in the book. the conditions and cures are very well discribed.

k



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terrymason
post May 17 2007, 09:45 AM
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QUOTE(rhodyguy @ May 17 2007, 07:35 AM) *

any other symptoms? snapping/popping back thru the carbs as you open the throttle plates?

-Yep

back fire on decel?

- No, but my wbo2 gauge reads very lean on decel. My sensor is near the exhaust tip though, so it could be fresh air being sucked in.



I'm using the Dellorto superperformance book, although it sounds like the ideas are all the same.

The passenger (1) side carb seems fine, maybe alittle rich, and the driver side (2) seems lean, and backfires out the carbs. It sounds like you may be on to something here. I'll go back to my book.
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Posts in this topic
terrymason   Correct fuel pressure for dual carbs?   May 16 2007, 11:16 PM
john rogers   I ran 3.5 PSI with my four cylinder engines and ab...   May 17 2007, 12:23 AM
So.Cal.914   3.0 lbs.   May 17 2007, 02:03 AM
lotus_65   2.5 lbs   May 17 2007, 06:25 AM
SGB   60s are mighty big. How big is the motor? for ma...   May 17 2007, 06:59 AM
type11969   The self-regulated pumps sold by VW shops for dual...   May 17 2007, 08:33 AM
rhodyguy   any other symptoms? snapping/popping back thru the...   May 17 2007, 09:35 AM
terrymason   any other symptoms? snapping/popping back thru th...   May 17 2007, 09:45 AM
terrymason   I'm running 60 idle jets, 140 main jets, and 1...   May 17 2007, 09:39 AM
rhodyguy   sometimes a bit more info is helpful. no mention o...   May 17 2007, 09:52 AM
terrymason   sometimes a bit more info is helpful. no mention ...   May 17 2007, 10:34 AM
type11969   If you have the dellorto superperformace tech book...   May 17 2007, 09:58 AM
rhodyguy   the only reason i suggest turning the idle up is t...   May 17 2007, 10:49 AM
Travis Neff   does your pump rattle a bunch? That would be an i...   May 17 2007, 10:57 AM
terrymason   does your pump rattle a bunch? That would be an ...   May 17 2007, 11:22 AM
type11969   Check to make sure your idles are clear, also veri...   May 17 2007, 11:00 AM
terrymason   I talked to Aaron from CB performance, who was awe...   May 17 2007, 11:08 AM
Gint   I talked to Aaron from CB performance, who was aw...   May 17 2007, 05:36 PM
rhodyguy   "no ammount of adjustments"...are you re...   May 17 2007, 11:15 AM
terrymason   "no ammount of adjustments"...are you r...   May 17 2007, 11:18 AM
type11969   Plugged idle jet or circuit   May 17 2007, 11:16 AM
Travis Neff   Sounds like you do have a facet pump. The CB rota...   May 17 2007, 11:24 AM
rhodyguy   facets suck. get #3193. the canister to the right ...   May 17 2007, 11:34 AM
terrymason   I have some 46 and 52 idle jets at home (60s insta...   May 17 2007, 02:18 PM
type11969   I'm running a 1.8, little warmed over than sto...   May 17 2007, 02:39 PM
anderssj   Terry, I have some spare jets here in Yorktown--m...   May 17 2007, 04:01 PM
type11969   :agree: I fought with my dells and got sick of s...   May 17 2007, 06:38 PM
r_towle   You may have a simple air leak at the intake bolts...   May 17 2007, 09:50 PM
terrymason   Well, I believe that I've found the main probl...   May 17 2007, 10:10 PM
Gint   It just plain makes good sense. You'll establ...   May 17 2007, 10:18 PM
terrymason   I'm still fighting this thing, and am ready to...   Jun 3 2007, 05:00 PM


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