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don.ville 
Samba YardMan
Joined: February 07, 2008
Posts: 2830
Location: West Palm Beach, FL
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 Posted: Sat Jun 12, 2010 5:05 pm Post subject: 34 pict flooding and hard starting when warm - needle valve |
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1600 DP engine.
34 pict 3 VW Solex carburetor.
Bosch SVDA distributor.
Compufire electronic ignition.
Bus has been driving very well.
Idles and runs smooth.
EXCEPT: starting. When it is warm I have to crank forever before it starts.
Worse on a very hot day here in FL, 95+ (felt like it)
crank, crank, crank, crank, (with pedal 3/4 way down and held steady), crank, crank, putt, putt, putt, putt, vroom.
I feel like just leaving it idling sometimes cuz the long crank time is SOOO annoying.
Also mileage is still pretty low at 19mpg
Well, after searching and reading, I decided to check everything out and then attack a potential bad needle valve.
Make sure bus is not running rich all the time by reading the spark plugs. They look nice and brown:
Coil check replaced it last month:
Put back compufire with new wires, cap and rotor last month, even changed vacuum line to vacuum advance distributor:
Check Compufire trigger wheel:
Make sure idle jet has not drifted and is still snug:
Take it for a long drive to get it very warmed up. I wanted the engine bay to be toasty, so I drove around in 3rd gear in local traffic.
Then I backed it into the garage and got a mirror to peek down the carb throat.....
Fuel is just running down the carb throat, dripping away. I took my time to get the mirror and tools too, so must be quite a bit after every trip leaking away killing my MPG and making the bus hard to start.
I remove the top of the carb to change the needle valve:
Fuel dripping from everywhere it looks like
I use my brand new carb as a parts donor and take the needle valve and two washers from it.
I installed the needle valve on the right with 2 washers.
While I am there, since my choke plate sticks sometimes, I decide to remove the material that was causing it to bind.
Did a couple of test runs on a hot day last Friday, and it all looks good so far. It doesn't start on the first revolution, but no 10 second cranking at least for now.
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Campy
Samba Member
Joined: January 10, 2005
Posts: 4933
Location: Chico, CA
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| Posted: Sat Jun 12, 2010 6:12 pm Post subject: |
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Make sure that the fuel tank is being vented and see if there is any fuel in the crank case.
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don.ville
Samba YardMan
Joined: February 07, 2008
Posts: 2830
Location: West Palm Beach, FL
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| Posted: Tue Jul 13, 2010 9:06 pm Post subject: |
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Carb still seems to be "sweating" fuel into the throat from the seams.
I have 2 washers on the needle valve.... anybody use 3 washers?
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FINEGERMANSTEEL
Samba Member
Joined: February 21, 2008
Posts: 261
Location: Spokane Wa
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| Posted: Tue Jul 13, 2010 9:34 pm Post subject: |
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most ive used was 2 but i went to one.not sure about 3?
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Culito
11010101
Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
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| Posted: Tue Jul 13, 2010 9:34 pm Post subject: |
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Ah, the ol' VW hot start dilemma.
I have this problem on my bug, too. It has that time frame of ~30 min or so after shutdown where I have to crank it forever. It will finally start, and I smell fuel when it does.
My single cab (which has a 34-3) does it too, but not as bad.
Possibly residual fuel pressure + ambient heat causing the fuel to expand and leak into the manifold, causing minor flooding?
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'64 standard w/2.0L type 4
'62 bug
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Campy
Samba Member
Joined: January 10, 2005
Posts: 4933
Location: Chico, CA
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| Posted: Tue Jul 13, 2010 11:00 pm Post subject: |
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I still think that the fuel tank is not getting vented. When it gets hot outside, pressure can build up in the tank, forcing fuel down through the carburetor and into the cylinders. Some 25 years ago, my bus was hard to start and I would smell fuel odor; once, fuel even got into the crankcase. I had been sold an unvented cap for my 1957 buses fuel tank, which caused the problem.
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PEPPE
Samba Member
Joined: August 24, 2003
Posts: 1068
Location: Roma Italy
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| Posted: Wed Jul 14, 2010 12:49 am Post subject: e |
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| i believe that the problem is that the needle valve does not have the dampening ball on the tip. most of the needle valves included in the rebuild kits are not good. i just use some gasket and the membranes of them. some needle valve are also dangerous... (they stick open) |
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Matt Miller
Samba Member
Joined: October 24, 2005
Posts: 282
Location: Costa Mesa, California
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don.ville
Samba YardMan
Joined: February 07, 2008
Posts: 2830
Location: West Palm Beach, FL
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| Posted: Wed Jul 14, 2010 8:53 am Post subject: |
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| Campy wrote: |
| I still think that the fuel tank is not getting vented. When it gets hot outside, pressure can build up in the tank, forcing fuel down through the carburetor and into the cylinders. Some 25 years ago, my bus was hard to start and I would smell fuel odor; once, fuel even got into the crankcase. I had been sold an unvented cap for my 1957 buses fuel tank, which caused the problem. |
I have the stock fuel cap with the word KOMBI stamped on it. that's vented OK right?
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bill may
Samba Member
Joined: August 27, 2003
Posts: 14160
Location: san diego,ca
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| Posted: Wed Jul 14, 2010 9:08 am Post subject: |
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| don.ville wrote: |
I have the stock fuel cap with the word KOMBI stamped on it. that's vented OK right? |
that is not a stock gas cap for a 67 and older bus,but they do work ok. the sv2s club bus has one.
the original cap is aluminum with huge vw emblem on it.
the fuel line metal tube is held to fan housing with the clamp correct? it keeps the metal tube from touching hot things like exhaust tubes and such. how old is your fuel pump? when i replace the inlet/ needle valve i always reuse the original fiber washer with the new needle valve.
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don.ville
Samba YardMan
Joined: February 07, 2008
Posts: 2830
Location: West Palm Beach, FL
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| Posted: Wed Jul 14, 2010 10:14 am Post subject: |
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| bill may wrote: |
that is not a stock gas cap for a 67 and older bus,but they do work ok. the sv2s club bus has one.
the original cap is aluminum with huge vw emblem on it.
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Thanks will look for it. Mine is still vented around the edges though right?
| bill may wrote: |
the fuel line metal tube is held to fan housing with the clamp correct? it keeps the metal tube from touching hot things like exhaust tubes and such. how old is your fuel pump? when i replace the inlet/ needle valve i always reuse the original fiber washer with the new needle valve. |
New fuel pump installed January 2010
fuel Pressure less than 3psi at idle and above:
fuel line clamp (photo taken during process of removing engine, so some tin is missing) Intake elbow measured at 120degF after running with infrared gauge.
I'm using the one on the RIGHT with 2 washers
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Campy
Samba Member
Joined: January 10, 2005
Posts: 4933
Location: Chico, CA
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| Posted: Wed Jul 14, 2010 11:38 am Post subject: |
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When the bus has been parked for some time on a hot day, remove the fuel cap and listen for a sound; if there is a sound, there was a change in pressure. Any sound means that the cap is not venting. A bad cap can cause a fuel tank to have a pressure buildup in it or a vacuum.
Years ago, the owner of the local VW supply store sold me a new fuel cap that he swore was a vented one, and it wasn't vented so I returned it. There was a batch of new fuel caps being sold by a distributor as vented, back then, that were not vented, so listen for the sound.
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Culito
11010101
Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
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| Posted: Wed Jul 14, 2010 3:17 pm Post subject: |
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I'm having this issue on two different vehicles and I know for a fact that both my tanks are vented.
On my SC I have the original large-VW emblem cap, and somebody even poked a hole in it. It never builds vacuum or pressure.
On my bug the tank is vented by a line off the neck of the tank, which I double checked.
(Not to hijack)
The bug is worse, and it has the new style needle valve without the ball, so that might be something...
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Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
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Campy
Samba Member
Joined: January 10, 2005
Posts: 4933
Location: Chico, CA
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| Posted: Wed Jul 14, 2010 3:59 pm Post subject: |
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A gas cap with a straight through hole in it can be dangerous.
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Culito
11010101
Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
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| Posted: Wed Jul 14, 2010 4:03 pm Post subject: |
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| Campy wrote: |
| A gas cap with a straight through hole in it can be dangerous. |
That's why I poke holes in ALL of my gas caps. Hell, I think I'll just start running without 'em.
_________________
Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
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moose14623
Samba Member
Joined: May 10, 2011
Posts: 2
Location: Rochester, NY
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| Posted: Tue May 10, 2011 11:48 am Post subject: |
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Hey man, Did you eventually solve this issue?
Regards, Moose.  |
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don.ville
Samba YardMan
Joined: February 07, 2008
Posts: 2830
Location: West Palm Beach, FL
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| Posted: Mon May 12, 2014 2:44 pm Post subject: |
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| moose14623 wrote: |
Hey man, Did you eventually solve this issue?
Regards, Moose. |
I bought a rebuilt carb from Harney. Best investment of $225 ever.
Time has run it's course, and that carb is now flooding the intake after the engine is warm.
Some serious flooding too!!!
I swapped float needles, and it still does it.
This carb runs SO well, I want it fixed without having to swap to another carb 
Just got a rebuild kit, and going to check fuel pressure and other stuff.
_________________
67 Standard 11 window How I Keep My Bus Alive
04 Jetta TDI Page (SOLD)
01 Mexican Beetle Hello Kitty Rescue (SOLD)
29 Ford Model A Rat Rod (SOLD)
2015 Audi A8L TDI Quattro
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