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J1
Samba Member
Joined: February 10, 2014
Posts: 698
Location: SoCal
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 Posted: Wed Apr 16, 2014 11:27 pm Post subject: |
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| Harleyelf wrote: |
Check to see that your shredded fast idle o-ring didn't leave a chunk behind.
Check for air leaks.
Check slow jet for obstructions. |
Don't issues like vacuum leaks and clogged jets cause LOW or ERRATIC idle, not HIGH idle?
Generally speaking, is high idling bad if I do short trips around town? Just want to be sure I won't be doing any damage in the meantime.
And is there a resource that explains what each part of a 34-3 do? Just curious. I've searched quite a bit and seen the vintage vw training videos, but they're not all that helpful.
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1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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Volfandt
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Joined: March 15, 2012
Posts: 500
Location: Knox County, East TN
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| Posted: Thu Apr 17, 2014 5:58 am Post subject: Sounds like the carb has issues |
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Setting the timing at 3000 rpm is the tried and true method now a-days. 28 to 32 is the proper range w/most ending up at around 30. Since Dist's run the gammit in build quality and advance curve designs, the advance setting at idle is really not important.
Setting the timing statically and/or at idle is generally used to get the engine started, setting the timing at 3000 rpm is to fine tune it.
So if your timing is between 28 - 32 degrees BTDC @ 3000 rpm timing isn't the issue.
You say the valves are set right so that shouldn't be an issue either.
The fact that you can't adjust the idle speed w/the carbs adjustments IS an issue.
Since the engine is idleing high and both the the volume and bypass have no effect, the carb HAS to be drawing fuel from somewhere.
1st guess would be that the tips of both adjusting screws are damaged and not closing off the ports when fully screwed in.
Take them out and inspect each tip, making sure they come to a very small rounded point.
Blow compressed air through the passages making sure you can feel air coming out of the idle ports in the venturi.
2nd guess is something I ran into on my 34-PICT/3, check the float and make sure theres no fuel leaking into it. IF so it wil be too heavy to close the off the fuel into the float bowl and the excess fuel has to go somehwere, whch is mainly through the vents into the venturi.
Whatever is causing the issue will deteriorate. And your engine will fail you at the most in-oppurtune time, like in bumper to bumper traffic or when miles and miles away from home. Murphys Law......
Once setup properly these 34-PICT/3's operate quite well in all driving conditions.
Good luck
Dave
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1972 Karmann Ghia, the Dragon slayer.... |
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Lionhart94010
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Joined: January 04, 2005
Posts: 1417
Location: SF Bay Area / Silicon Valley / So Cal
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| Posted: Thu Apr 17, 2014 7:57 am Post subject: |
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If it’s a 40 year old carburetor your throttle shaft probably does not seal properly and it is idling high because it is sucking in air through the throttle shaft, typically that make them run poorly because that causes your AF to be lean(also sometimes this makes it so when clean your carburetor it runs worse).
It is near impossible to properly tune a 34-PICT/3's with a loose throttle shaft, check yours for side play: up, down, forwards, backwards, it should not move ;0)
If it’s loose get it fixed…
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Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 2015 GSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC, 72 KG GT that now lives in Australia, 12 JSW TDI, 2015 GSW TDI, 2023 Tiguan
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm |
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OLD VW NUT
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Joined: February 23, 2011
Posts: 2776
Location: High Desert of Washington 98823
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| Posted: Thu Apr 17, 2014 9:10 am Post subject: |
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| Jawon wrote: |
| Harleyelf wrote: |
Check to see that your shredded fast idle o-ring didn't leave a chunk behind.
Check for air leaks.
Check slow jet for obstructions. |
Don't issues like vacuum leaks and clogged jets cause LOW or ERRATIC idle, not HIGH idle?
Generally speaking, is high idling bad if I do short trips around town? Just want to be sure I won't be doing any damage in the meantime.
And is there a resource that explains what each part of a 34-3 do? Just curious. I've searched quite a bit and seen the vintage vw training videos, but they're not all that helpful. |
Signs of a vacuum leak is usually a high idle. And blipping the throttle usually results in an even higher idle that slowly lowers rpm's back to a high idle. With dual carbs it usually means they aren't balanced well. If you can quickly kill the engine (from idle) by placing your hand over the carb intake it may not be much of a leak. If the engine doesn't die fast when you cover the carb the leak may be a big one. Plugged jets cause a lean condition often with belch back through the carb. Different symptoms.
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kreemoweet
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Joined: March 13, 2008
Posts: 3899
Location: Seattle, WA
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| Posted: Thu Apr 17, 2014 7:58 pm Post subject: |
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Another vote here for the butterfly-hole-plugging trick discussed on the aircooledtech.com page referred to above.
I had exactly the same bad symptoms as the O.P., with a variety of 009 dist.'s and 34 PICT-3's, and even with
a new 034 SVDA distributor. After plugging the hole with a pop-rivet (easy to do, and easy to undo), the improvement
was remarkable. The carb adjustment screws actually started working as intended. I could actually get the idle down
below 1000 rpm, and have it rock-steady in all weather conditions. The power and throttle response betterment was
unmistakable.
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J1
Samba Member
Joined: February 10, 2014
Posts: 698
Location: SoCal
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| Posted: Thu Apr 17, 2014 11:33 pm Post subject: Re: Sounds like the carb has issues |
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Thx for all the great leads. Will try them all...
| Harleyelf wrote: |
Check to see that your shredded fast idle o-ring didn't leave a chunk behind.
Check for air leaks.
Check slow jet for obstructions.
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Hmm, good point, didn't think about where the o-ring residue went.
| OLD VW NUT wrote: |
| Signs of a vacuum leak is usually a high idle... If you can quickly kill the engine (from idle) by placing your hand over the carb intake it may not be much of a leak. If the engine doesn't die fast when you cover the carb the leak may be a big one. |
I would've guessed a carb vacuum leak would cause LOW idle since it's sucking more air in, but I guess that shows how much I know.
| Volfandt wrote: |
1st guess would be that the tips of both adjusting screws are damaged and not closing off the ports when fully screwed in...
2nd guess is something I ran into on my 34-PICT/3, check the float and make sure theres no fuel leaking into it. IF so it wil be too heavy to close the off the fuel into the float bowl and the excess fuel has to go somehwere, whch is mainly through the vents into the venturi. |
Interesting tips!
| kreemoweet wrote: |
Another vote here for the butterfly-hole-plugging trick discussed on the aircooledtech.com page referred to above...
After plugging the hole with a pop-rivet (easy to do, and easy to undo), the improvement was remarkable. The carb adjustment screws actually started working as intended. |
Yes, have had this in mind. Will keep this as an option if others don't work.
Thx all! These are the types of specific troubleshooting tips I was hoping for.
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1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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J1
Samba Member
Joined: February 10, 2014
Posts: 698
Location: SoCal
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| Posted: Sat Apr 19, 2014 1:42 am Post subject: |
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All looks fine. Btw, that trick about putting your hand over the carb was cool... hand got sucked in firmly and the engine died on a dime.
So the last option is riveting the butterfly hole. Bought a $5 rivet gun at harbor freight. Had to fight with it, dismantle it, multiple times, rig it since it didn't quite fit on the butterfly, and then when I finally got the rivet in, the rivet hole was still plugged up with the pin so I had to pull out the drill. I'm having a hard enough time figuring out my ghia let alone the tools too!
Anyway, it's done and I'm really hoping I'm one of the lucky rivet success stories! Don't want to wake up the neighbors so will start her up this wkend. Happy Easter!
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J1
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Joined: February 10, 2014
Posts: 698
Location: SoCal
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| Posted: Fri Apr 25, 2014 1:41 pm Post subject: |
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Just to close the loop, I put in the rivet and idle has come down. Thx all. I'll add an SVDA to my christmas wish list.
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