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Matthew Samba Member
Joined: January 29, 2004 Posts: 1760 Location: Eastern Tennessee
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Posted: Thu Aug 13, 2009 8:21 am Post subject: 40 IDFs Need Help from the Pros |
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I recently installed a pair of Italian 40IDFs on my 1600. Before installation I had them apart, soaked in pale of carb cleaner, rinsed, blew though all passages. The were carefully reassembled with new carb kits and the float levels were set at 10mm. Fuel pressure w/ stock pump is 3psi at 2500 rpm and 3.5 psi at idle.
Now for the problem. When I shut the car off fuel runs down the throat on #4. Even if I clamp the fuel line from the pump first (fuel pressure to 0) and shut off it still happens. Engine doesn't have to be hot to make it happen. Looking down that throat with a flash light, the fuel seems to appear from around the throttle shaft on the side towards the float bowl. It will keep letting fuel flow until the float bowl level is very low (just barely above the check valve for the accel pump) I'm getting ready to pull this carb and see if I can figure it out. What should I be looking for?
Thanks in advance _________________ 1965 Beetle sedan
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sturgeongeneral Samba Member
Joined: June 23, 2005 Posts: 2460 Location: Sacramento, California
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Posted: Thu Aug 13, 2009 9:08 am Post subject: |
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I would double check float height and inlet valve. _________________ Street legal fiberglass rocket ship
2005 Lotus Elise supercharged
1974 Chevy Corvette
My fiberglass car collection!
In honor of bowtie56jw:Another victim of the nasty "C" Praying for ya Jeff!
My exwife said if I towed home one more bug she would leave me. You know, every once in a while I miss her |
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[email protected] Samba Member
Joined: August 03, 2002 Posts: 12785 Location: Salt Lake City, Utah
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Posted: Thu Aug 13, 2009 9:31 am Post subject: Re: 40 IDFs Need Help from the Pros |
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usually it means the idle air bleed is plugged.
John
Aircooled.Net Inc. _________________ It's just advice, do whatever you want with it!
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Matthew Samba Member
Joined: January 29, 2004 Posts: 1760 Location: Eastern Tennessee
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Posted: Thu Aug 13, 2009 9:32 am Post subject: |
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sturgeongeneral wrote: |
I would double check float height and inlet valve. |
I switched to the original inlet valve and reset the float height with the same results. I can stop the fuel flow to the carb and then shut it off and it still happens. It will continue to dribble until the bowl level is very low. Only happens on that one throat. When I pier down the throats with the engine running, I do not see any fuel -- only after I shut it off does it appear around the throttle shaft and cover the throttle plate. _________________ 1965 Beetle sedan
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ALB Samba Member
Joined: August 05, 2008 Posts: 3480 Location: beautiful suburban Wet Coast of Canada
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Posted: Thu Aug 13, 2009 10:56 am Post subject: |
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Did you check what John suggested? _________________ On a lifelong mission to prove (much to my wife's dismay) that Immaturity is Forever!! |
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Matthew Samba Member
Joined: January 29, 2004 Posts: 1760 Location: Eastern Tennessee
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Posted: Thu Aug 13, 2009 10:59 am Post subject: |
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Nope, Looks like John was typing at the same time I was. I just saw is post. I'll jump on that and report back. Thanks! _________________ 1965 Beetle sedan
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udidwht Samba Member
Joined: March 06, 2005 Posts: 3777 Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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Posted: Thu Aug 13, 2009 1:51 pm Post subject: |
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Yes, check what John suggested. Those need to be clean as a whistle. Be very sure when you place the carb top gasket on that nothing is obstructing the passage ways. Re-verify the float height with the gasket in place 10-11mm. Did you replace the needle/seats? |
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Matthew Samba Member
Joined: January 29, 2004 Posts: 1760 Location: Eastern Tennessee
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Posted: Thu Aug 13, 2009 2:19 pm Post subject: Re: 40 IDFs Need Help from the Pros |
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[email protected] wrote: |
usually it means the idle air bleed is plugged.
John
Aircooled.Net Inc. |
The man is a genius, pure genius. I removed the idle jet from the offending throat and with the top off the carb blew through the little air duct that goes down to the idle jet location and viola problem solved. There must have been a little sliver of gasket material in there.
I readjusted all the idle volume screws and consequently had to lower the idle a bit. She is running smooth. I went from Kadrons to 40 IDFs and what a difference. It has more power and runs smoother throughout the rpm range. I'll save the Kadrons for a SP engine project, but I don't think I'll ever bother with them again for any DP head engines especially when they have performance cam and head work. _________________ 1965 Beetle sedan
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DarthWeber Samba Member
Joined: November 24, 2007 Posts: 7543 Location: Whittier,CA
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Posted: Thu Aug 13, 2009 2:27 pm Post subject: Re: 40 IDFs Need Help from the Pros |
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Matthew wrote: |
The man is a genius, pure genius. |
You asked for a pro! |
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Matthew Samba Member
Joined: January 29, 2004 Posts: 1760 Location: Eastern Tennessee
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Posted: Thu Aug 13, 2009 2:41 pm Post subject: Re: 40 IDFs Need Help from the Pros |
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DarthWeber wrote: |
Matthew wrote: |
The man is a genius, pure genius. |
You asked for a pro! |
I love TheSamba! That little tip saved me countless hours of frustration, plus I learned something today. _________________ 1965 Beetle sedan
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[email protected] Samba Member
Joined: August 03, 2002 Posts: 12785 Location: Salt Lake City, Utah
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Posted: Thu Aug 13, 2009 8:21 pm Post subject: Re: 40 IDFs Need Help from the Pros |
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you are one of the rare ones that actually follow my advice.
Good job.
Now tune them and stop mosquito foggin'
John
Aircooled.Net Inc. _________________ It's just advice, do whatever you want with it!
Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net
"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net |
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