Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

> Correct fuel pressure for dual carbs?
terrymason
post May 16 2007, 11:16 PM
Post #1


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174



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.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
type11969
post May 17 2007, 09:58 AM
Post #2


Senior Member
***

Group: Members
Posts: 1,231
Joined: 2-December 03
From: Collingswood, NJ
Member No.: 1,410
Region Association: North East States



If you have the dellorto superperformace tech book, it is definitely in there, I don't have the book in front of me though so I can't quote the page. I believe it is after the troubleshooting section for the DRLAs. There is a small diagram indicating the height needed at open/closed positions.

It is easy, potentially time consuming though to get dead on. All you have to do is pull the carb top, measure the float position at the extents of its travel against the bottom of the carb top, and set the position to be 5-6mm from the bottom of the carb top in the float highest position, and 12-13mm in the lowest. You change the highest position by bending the forklike tabs that engage the needle valve, and you change the lowest position by bending the tab that contacts the part of the carb top that retains the float (opposite side of the float from the forklike tabs). I pull off the carb top gasket to get an accurate reading. Be careful that the spring loaded pin in the needle valve is not compressed at all during the stroke of the float. This will close the valve prematurely. Make sure it is the forklike tabs that close the valve.

If one float is set to high and the other set too low, one carb will certainly be richer than the other due to the different fuel levels in the bowl (and may also cause fuel to dribble out of the bowl down the carb throat).

I've been fighting with my dells for the past few weeks too, so I feel your pain. I think I solved my biggest issue by realizing that the needle valve were getting closed before I thought because I was compressing that spring loaded pin. The symptom was a high rpm leanout like I was running out of fuel. The way the floats were set, basically I was.


-Chris


User is offlineProfile CardPM
Go to the top of the page
+Quote Post

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


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 11th July 2025 - 08:58 AM