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Thu Mar 13, 2008 7:19 pm

ALL RIGHT... now I think I am getting to the bottom of it (a little late though I admit). I disected the H30/31 and found a few interesting things... The Idle Jet was a 50, the Main Jet was a 120, and the air correction was a 125z.

Looks to me as though the 30/31 jets were to small for a 1600 cc motor. At least that is the conclusion I came to after reading the great replies above and countless articles on the vw_resource. It seems as though the carb was set up for a smaller 1300cc motor.

It also answers the question as to why my car is running much better...but not great yet. That would be because my mechanic moved my 50 idle jet over to the 34pict/3 and it should be a 55 or 60. The main is a 127.5, which would be a good one for the 30/31...hense why it seems to run much better now with this rebuilt carb and Vacuum Advance distributor.

Thu Mar 13, 2008 7:22 pm

Oh yah... one last thing. My mileage went way up! I go approximately 100 miles a week and use 5~5.5 gal of fuel. This week, I only used 4.3!

Sat Feb 21, 2009 12:08 pm

I realize that it has been a while since I posted anthing on this...but I believe the saga is finally over...the orginal H30/31 carb croked on me and I could not get the car to start without holding the pedal to the floor and really cranking the starter. So...I replaced it with a new one and lone behold, some of the same original issues started right back up again. This time, the story is coming out differently!

So...what did I do differently this time? Here is what I did:

- Switched the Idle and Power jets back into the correct location! They came again from the factory in the wrong position for most cars.
- Changed the Main Jet to a 125 (from a 120)
- Changed the Idle Jet to a 55 (from a 50)

Now the car runs GREAT! I credit the guys at www.vwresource.com for responding to some of my previous posts and for the great explanations they give at their website for carbs.

SO....if you are running a Beetle, and a 1600 Single Port with an H30/31 carb, use a SVDA dizzy, 125 main jet, 55 Idle Jet and a 65 power jet. You will be suprised on the smooth response!