engine and drivetrain Weber 38/38 info anyone?

[PSloan]

The 38 on my engine is running way rich. No matter how I tune it its fouling the plugs and raw gas is coming out the tailpipe. What are the proper jets for running this carb on an 02? it has 185s on it now. how the hell do i tone it down?

[pkbinplano]

(nt)

[PSloan]

good question. I'll check tomorrow.

[mikem]

But gas out the tailpipe is more than rich!

As Paul said, check the float.

Here's my 38DGES story from previous post:

I think that the Weber 38 is a bit too large a carb for a stock motor. Not enough air volume at lower rpms to get the best effect through the big barrels. So it has to be set "too" rich. Always smells "fuely."

Original out-of-the-box (from Maximillian):

Idles-45

Mains-142

Air Corr-185

Current:

Idles-55

Mains-140

Air Corr-170

I think that it's at least a little better than the original 38's jetting. It's rich at idle, but, I thought that the stumble around the neighborhood was leanness because not enough air was flowing through the big barrels at lower RPM to draw adequate fuel through the main jets. So I have bumped the idle jets since they are in operation during transition to full mains.

This was based on very limited knowledge of carb function, so my theory may not be accurate.

[PSloan]

thanks for the info. Where can I get jets for it?

[pbryantr]

http://www.piercemanifolds.com

[mikem]

Got this from Maximillians shortly after I installed my carb and had questions for them.

•Weber advice from Paul and Matt at Maximillian Importing:

BASIC CARB TUNING RULES:

Rule 1: you want the car to idle as lean as possible

Rule 2: Don't sacrifice smoothness for leanness though!! Lean it out (by tightening the idle mix screws) until it starts to lose it's smoothness - then back out the screws 1/2 turn.

Rule 3: The lower the idle speed - the leaner it can / needs to be, if you're raising the idle speed - make a tiny corresponding enrichment at the screws.

Rule 4: I've always let my cars idle a bit high - maybe 950 -1000rpm. they just seem to "settle in" around this when mixture and speed are ping ponged back and forth. trying for the perfectly smooth factory 850rpm idle in a 25 yr. old car, is like searching for a rust free 3.0 CS coupe - It rarely happens!

Rule 5: TIMING: You want as much ignition / distributor advance as you can stand - as long as it doesn't ping at full throttle up hills or at 3000 rpm w. pedal to the floor - you'll get the most performance from more advance.

a. When you advance the timing - it will generally raise the idle speed.

Make corresponding idle speed adjustment back to 900-1000- then corresponding (leaner) mix adjustment.

b. Bigger carbs just seem to like more "initial" advance at idle - it improves the throttle response and smoothness off idle.

More timing comments:

Have you tried advancing the timing yet (beyond the stock setting)? In every case we've had where there was a problem similar to yours, increasing the timing a bit has smoothed it out. My experience has led me to completely abandon the timing light as a tuning tool for the '02.

My method for adjusting the timing is to basically turn the distributor counter clockwise until the idle get rough and then just back it off until it smoothes out. Then go drive up the nearest hill and 4th gear and listen for pinging, then, if it pings, back off the timing until it goes away. Fresh points and stuff couldn't hurt, but I'll bet the timing will fix it.

Now go to it! be patient, be methodical, and do one step at a time to avoid too many variables!!!

[mikem]

Maybe local "import parts" or VW shops.

[punchesdfw]

Pat, I bought that carb new from TEP and paid extra to have it jetted and properly set-up for the '02. It should have the right jets in it. But.., you never know.

[Guest Anonymous]

IIRC, I have each of the two mixture screws out 1 full turn, not the 2 full turns commonly posted. Two full turns is WAY too rich--at least on my application. The carb has the same jets that were in it when it came new from Max. My car has about 20k on the engine (9:1 pistions, Tii exhaust manifold, elec. ignition, etc.) and idles smoothly and pulls strongly. So, so much better in so many ways than a 32/26.

HTH,

John

72 Sahara