 Dual Weber IDF 40s, Carb Rookie question... |
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| malcolm2 |
 Apr 25 2023, 01:53 PM
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#1
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Advanced Member  Group: Members Posts: 2,749 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States 
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Hello everyone. I will preface by saying that this is an engine from a 914. (IMG:style_emoticons/default/piratenanner.gif)
But it is in my VW Bus. Just now getting it moving down the road. Everything is new. Carbs are new and I am a carb rookie, as well. Bought them from Aircooled.net and had them cleaned and set-up for the bus. My 914 has L-Jet FI, this group has taught me enough about that system to be dangerous. So here is my question for the carb experts. What should the Pump Valve spray look like? It seems erratic and drippy. It kicks in 1st as I open the throttle, not a spray but pore, really. I will say that I see that in all 4.   |
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| 930cabman |
May 1 2023, 10:35 AM
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#2
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Advanced Member Group: Members Posts: 4,594 Joined: 12-November 20 From: Buffalo Member No.: 24,877 Region Association: North East States
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I run 12+mm on my 40IDF Weber floats. I prefer to have the fuel level a bit lower as opposed to higher. Is your fuel pressure in the 1 - 3 psi range? I run around 1.5 and seems to work just fine.
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| malcolm2 |
May 1 2023, 12:13 PM
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#3
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Advanced Member Group: Members Posts: 2,749 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States
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QUOTE(930cabman @ May 1 2023, 11:35 AM)  I run 12+mm on my 40IDF Weber floats. I prefer to have the fuel level a bit lower as opposed to higher. Is your fuel pressure in the 1 - 3 psi range? I run around 1.5 and seems to work just fine. That is my next recommendation.... As I started doing test drives around the hood, it was suggested to run at 3.5 psi. Recently, it was recommended to drop to 2.5, so once I get the carbs back on and the idle adjusted and sync'd, I will drop the pressure. Whole thing started when I noticed the pressure was 1.5 not sure what happened with that, but since then, I have made enough changes to pretty much start from scratch. So here I go... |
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| 930cabman |
May 1 2023, 01:37 PM
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#4
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Advanced Member Group: Members Posts: 4,594 Joined: 12-November 20 From: Buffalo Member No.: 24,877 Region Association: North East States
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QUOTE(malcolm2 @ May 1 2023, 12:13 PM) QUOTE(930cabman @ May 1 2023, 11:35 AM) I run 12+mm on my 40IDF Weber floats. I prefer to have the fuel level a bit lower as opposed to higher. Is your fuel pressure in the 1 - 3 psi range? I run around 1.5 and seems to work just fine. That is my next recommendation.... As I started doing test drives around the hood, it was suggested to run at 3.5 psi. Recently, it was recommended to drop to 2.5, so once I get the carbs back on and the idle adjusted and sync'd, I will drop the pressure. Whole thing started when I noticed the pressure was 1.5 not sure what happened with that, but since then, I have made enough changes to pretty much start from scratch. So here I go... For me 1.5 works great (on the street), a track machine might be different and I have never ran the float bowls empty with 1.5 psi. Staying on the low side makes sense for me. |
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Posts in this topic
malcolm2 Dual Weber IDF 40s Apr 25 2023, 01:53 PM
malcolm2 Maybe the video will help. Close to the end, not ... Apr 25 2023, 04:35 PM nditiz1 So John from ACN is a master with carbs. Buying h... Apr 25 2023, 06:07 PM r_towle Sounds like they are not synced.
One cylinder soun... Apr 25 2023, 06:59 PM
Superhawk996
Sounds like they are not synced.
:agree:
To a... Apr 25 2023, 08:16 PM
malcolm2
Get the book on how to tune webers.
Syncing them... Apr 25 2023, 09:50 PM r_towle What carb linkage are you using?
Have you adjusted... Apr 25 2023, 07:02 PM malcolm2
What carb linkage are you using?
Have you adjuste... Apr 25 2023, 09:02 PM Superhawk996 Don’t worry about IDF specific book. I personal... Apr 26 2023, 06:32 AM nditiz1 "You can convince yourself of this truth by d... Apr 26 2023, 07:30 AM malcolm2
"You can convince yourself of this truth by ... Apr 26 2023, 07:53 AM rhodyguy FWIW, AC.net is out of biz. Doors closed. The webs... Apr 26 2023, 08:00 AM malcolm2 ACN website does leave a bit of the door open for ... Apr 26 2023, 08:13 AM rhodyguy Can you compare the exposed threads side to side? ... Apr 26 2023, 08:23 AM malcolm2
Can you compare the exposed threads side to side?... Apr 26 2023, 08:50 AM rhodyguy 2 filters? The middle canister is a filter. I got ... Apr 26 2023, 08:59 AM malcolm2
2 filters? The middle canister is a filter. I got... Apr 26 2023, 12:20 PM rhodyguy Does the jet dribble when the fuel pump is energiz... Apr 26 2023, 09:12 AM sportlicherFahrer The Tomlinson book is on the CB Performance site a... Apr 26 2023, 09:50 AM rhodyguy ‘Email notification when back in stock’. Could... Apr 26 2023, 09:54 AM 930cabman I would bet on either the pump stroke is insuffici... Apr 26 2023, 10:08 AM r_towle I used two filters on my race car because the tank... Apr 26 2023, 02:10 PM 914werke Not to hijack the thread but has anyone see these ... Apr 26 2023, 04:45 PM nditiz1 Rich, I just check 3 sets of my carbs. All of the... Apr 26 2023, 05:59 PM 914werke Ya Ive never see it before & they are installe... Apr 26 2023, 06:03 PM sportlicherFahrer I believe that piece is a float bowl vent that was... Apr 26 2023, 07:27 PM malcolm2 Pulled the plugs and did a compression check befor... Apr 26 2023, 10:15 PM Superhawk996
Pulled the plugs and did a compression check befo... Apr 27 2023, 07:52 AM malcolm2 update......
I have chromoly push rods and swivel... Apr 29 2023, 02:35 PM nditiz1 Sounds fine.
I usually see if I can spin the push... Apr 29 2023, 02:40 PM r_towle So, I am lazy and I hate getting up and down 50 t... Apr 29 2023, 03:19 PM malcolm2
So, I am lazy and I hate getting up and down 50 ... Apr 29 2023, 03:43 PM nditiz1 Who said your valves were out? I think someone me... Apr 29 2023, 04:04 PM malcolm2 A couple folks mentioned valve noises, now after c... Apr 29 2023, 04:09 PM nditiz1 No that all seems fine. I didn't hear anythin... Apr 29 2023, 04:38 PM porschetub
No that all seems fine. I didn't hear anythi... Apr 29 2023, 06:22 PM malcolm2 Heads are Camper Specials from Type4store.com. The... Apr 29 2023, 06:48 PM r_towle After you have done this adjustment, did your comp... Apr 29 2023, 08:18 PM malcolm2 I did not adjust any valves. I checked each valve ... Apr 30 2023, 05:02 AM nditiz1 Was this a newly rebuilt engine?
Compression test... Apr 30 2023, 07:49 AM malcolm2
Was this a newly rebuilt engine?
Compression tes... Apr 30 2023, 03:24 PM PatMc Compression test on an engine that overfueling wil... Apr 30 2023, 09:29 AM 930cabman Rich, find out why. floats, mis adjustment, needle... Apr 30 2023, 01:43 PM rhodyguy If you verify the floats source new gaskets first.... Apr 30 2023, 02:02 PM malcolm2 This float setting does not seem to be accurate. ... Apr 30 2023, 03:42 PM Jack Standz
This float setting does not seem to be accurate. ... May 4 2023, 02:08 PM malcolm2 OK... the more i putzed with it, the more I could ... Apr 30 2023, 04:25 PM r_towle 10mm is correct. Not sure where 12mm came from
ht... Apr 30 2023, 04:29 PM r_towle Curious to know the differences you find between t... Apr 30 2023, 04:30 PM malcolm2 The floats on both carbs are 12mm. Post #11 has t... Apr 30 2023, 04:40 PM Superhawk996
The floats on both carbs are 12mm. Post #11 has ... Apr 30 2023, 06:36 PM r_towle In theory you are right.
The proper specification ... Apr 30 2023, 05:05 PM malcolm2
In theory you are right.
The proper specification... Apr 30 2023, 06:35 PM Superhawk996
In theory you are right.
The proper specificatio... Apr 30 2023, 07:07 PM r_towle The collective experience we have all had is that ... Apr 30 2023, 05:06 PM malcolm2
The collective experience we have all had is that... Apr 30 2023, 06:43 PM cgnj Based on video at idle you have at least one dead ... Apr 30 2023, 05:30 PM Superhawk996 I should have mentioned 10mm correlates to a highe... Apr 30 2023, 06:55 PM Superhawk996 Since you were looking for a book and the Tomlinso... Apr 30 2023, 07:02 PM porschetub
[quote name='malcolm2' post='3075047' date='May 1... May 1 2023, 11:34 PM malcolm2 Found some time last nite and I re-assembled the c... May 3 2023, 07:48 AM malcolm2 RE: Dual Weber IDF 40s May 3 2023, 07:49 AM Superhawk996 Good find. Usually you’ll only have 1 air bleed... May 3 2023, 08:19 AM malcolm2 I do have a vacuum can on the disty. Both carbs ha... May 3 2023, 01:59 PM rhodyguy Tomlinsons Weber book p.22 ….’pre-set your air... May 3 2023, 02:38 PM malcolm2
Tomlinsons Weber book p.22 ….’pre-set your ai... May 4 2023, 12:14 PM nditiz1
Tomlinsons Weber book p.22 ….’pre-set your a... May 4 2023, 04:44 PM malcolm2
[quote name='malcolm2' post='3075791' date='May 4... May 4 2023, 07:35 PM nditiz1 ACN recommends using the port over cyl 4. I use t... May 3 2023, 04:54 PM rhodyguy PM sent. May 4 2023, 12:56 PM malcolm2 I go back and forth on ethanol or pure. Nice to k... May 4 2023, 07:39 PM malcolm2 OK.... engine started. Had to give the idle screw... May 6 2023, 08:15 AM 930cabman Keep us in the loop as you get her purring. May 6 2023, 01:48 PM r_towle Synced ?
I’m hoping you nail it!
Rich May 6 2023, 02:28 PM malcolm2 I may have..... Flow matches on all barrels, idle ... May 6 2023, 03:12 PM malcolm2 youtube won't let me rotate..... but you can s... May 6 2023, 03:25 PM r_towle I’m still hearing sumpin wrong.
Still sounds lik... May 6 2023, 03:49 PM 930cabman How does she run? WOT? seems to idle ok May 6 2023, 05:07 PM malcolm2
How does she run? WOT? seems to idle ok
I woul... May 8 2023, 05:30 PM Superhawk996 Still sounding a bit like it’s bogging a little ... May 6 2023, 05:15 PM malcolm2
Are you sure your idle mix is tuned properly for... May 7 2023, 08:11 AM Superhawk996
Linkage removed
Speed Screw 1/2 turn in after to... May 7 2023, 01:18 PM Jack Standz Yes, fuel pressure could be the problem, if you t... May 6 2023, 05:52 PM malcolm2
If you want to tune these carbs, suggest getting... May 7 2023, 08:21 AM malcolm2 All day run with new plugs. Lots of adjusting etc.... May 6 2023, 06:56 PM Superhawk996 You’re running way too rich
Have you verified... May 6 2023, 07:15 PM malcolm2
You’re running way too rich
Have you verifie... May 6 2023, 07:46 PM Superhawk996
look a bit lean to me. Gray??
There are also a... May 6 2023, 11:11 PM malcolm2
You’re running way too rich
Have you verifie... May 8 2023, 05:37 PM Jack Standz
You’re running way too rich
Yes, +1. May 7 2023, 12:16 PM rhodyguy Now you’re seeing how small adjustments can resu... May 7 2023, 12:27 PM malcolm2
Now you’re seeing how small adjustments can res... May 8 2023, 09:32 AM Superhawk996 I wouldn’t judge by that 1.3mm variance in the a... May 8 2023, 06:50 PM r_towle The throttle plates should be visible from above t... May 8 2023, 07:13 PM malcolm2 OK so I should get smaller Weber IDF Idle Jets....... May 9 2023, 01:14 PM 930cabman
OK so I should get smaller Weber IDF Idle Jets...... May 9 2023, 01:20 PM nditiz1 50 idle are fine. I doubt you will need to go low... May 9 2023, 01:54 PM |
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