Need an Opinion............Again! (Page 1 of 2)

How did you time it? At idle or max?

Does the engine respond normally to adjustment to the idle and mixture screws?

Is the choke working right. I have to adjust mine spring and fall.

jim

When you're at a stoplight and it's started running fine again, do you still have your foot on the brake? Seems to me if you had a vacuum issue with the booster (which I don't think the '70 has, does it? ) it would be a problem all the time, not just during deceleration.

I'm thinking it's more of a mixture issue. Float level too low, not much fuel in the carb bowl, sloshes around and starves the motor during decel? Leaking needle/seat flooding it out when you get off the gas and close the butterfly? Also choke setting and proper operation as mentioned below. SVDA plugged into correct port on the carb? Does the 30-pict 3 have the same pilot jet on the right side of the carb as the 34's do? They often take some fiddling to get them in the correct spot to idle well.

Strange problem indeed. Let us know what you find.

Hiya Guys,

Thanks for the opinions and ideas.

For the sake of clarification, this Bus does not have vacuum assist brakes.  I believe those came out in the 71 model year.

Jim:  It was timed at idle (875 rpms) to 7.5* BTDC as per instructions from aircooled.net.  Engine was quite responsive to tweaking the carb - just about textbook in that regard.  I did mess around with the choke a bit.  The butterfly seemed to be stuck so I took the choke apart and freed up the butterfly.  Everything seems to be working as designed.  The butterfly is closed (horizontal) when the engine is cold and vertical when warmed up.  I was thinking that I might try making the choke open up a bit quicker by tweaking its setting.

Clancy:  I'll go over the vacuum leaks again.  I dunno where the SVDA might be leaking.  New sheperd's crook, and new vacuum hosing.  But this does seem like it might be a vacuum issue to me.

Jordan:  Yeah, I do know that a crummy brake booster will have definite affect on engine idle/performance.  Too bad I don't have one.  I could at least check that out!  Mixture?  That's on my mind.  I do have access to a tailpipe analyzer coming up in a couple of weeks.  I think I'll hold off tweaking the mixture until then.  SVDA is plugged into the proper (left side) vacuum port on the carby.  I'm not sure that the pilot jet is the same as on a 34PICT3 but it is in the pretty much the same relative position.  I have pulled that pilot jet and cleaned it and its seat.

Hank:  I'm guessing that you're referring to the vacuum booster line for power assist brakes.  If you are, in fact referring to something else, please clarify for me.

Thanks guys!  It is a bit of a mystery, eh?  I'll be sure to fill you all in when I find out what the problem(s) might be.  In the meantime, if anybody else has any ideas shoot 'em my way.

Tweek the choke ?????? I dunno about that ?? Has a Diapraghm assist that work's off vaccum !
  875 RPM is a Lil low Im usually 900 to 950 even up to a thousand on Dual Carb's !
  But if the fuel shut off solenoid is hooked up ! Should Idle ! Often they become disconnected during tune up's <<< Make sure !
  Now on a 30 pict series carb Cute Lil trick for non Idleing condition is to pull the Idle Jett's ! there two Brass Nut's on the passenger side of the carb / Car !
   8 mmm or a screw driver pull these Jetts and blow them out with carb spray and compressed air !
   I usually say Abbra Cadabra after I clean these Jett's and re- install for asthetic reason's ! Quite Impressive for the Novice to observe !
    Plugged Idle Jett's !!! Common V.W. Ailment on the 30 pict serie's carb !
    Now other thing's provided cleaning Jett's doesnt do it ! Would be to check Clutch isnt dragging !! Clutch that doesnt fully dis- engage can cause what you describe !
  But Urge you to blow out Jetts first and then make sure fuel solenoid wire is connected and also that it Click's !
   Post again with result's !
  As to Carb Tweekin the choke etc. <<<< Dont ! Tieing chokes open is a Chevy / Jethro approach on Choke assisted Carb's !
                                            Sean

Mike! I see your problem right there!!!.......the engine and engine compartment are simply way too clean for the engine to run properly!!! You might need to wipe some used oil/grease around in there to seal up any vacuum leaks! <grin!!>

Clancy

Is there condensation forming on the carb or the intake manifold just below the carb?

Last edited by CW (2009-06-04 13:08:57)

Hiya Clancy,

Hah!  That picture was taken with about 100 miles on the engine.  Since then it has picked up some of the usual dirt and grime.  At least enough so that it should work like any self-respecting VW engine!

Patty:  Yep, no gas smell.  But the thing is giving me a headache anyway!  LOL

CW:  Nope.........no condensation.  The manifold preheat tubes were in excellent shape just before installation.

Anthony:  Funny about your comment............the fuel pressure was actually too high and I adjusted it down a bit.  That seemed to help the condition for a while.  Sean suggested basically the same approach - clean out those jets.  And I will be getting to that late today or tomorrow.  Also a good point about the acceleration/stumble thing.  I'm not getting a stumble but a bit of a hesitation now and then especially when the engine gets lugged (which I try to avoid).

Thanks agin all!  With your comments and ideas I've got a few more areas to check out.