A little black smoke on acceleration, Weber 40's Options

[Carlitos Way]

Still trying to hone in my webers. I'm getting a little black smoke and quite a bit of gas smell from my weber 40's on an otherwise stock 2.0 L engine (no modified cam).

32mm venturis

F11 Emulsion

55 Idle Jets

125 Main

180 Air

The car pulls fairly nice... but I'm hoping to... avoid NOXing myself and others as I drive...

[jwalters]

(IMG:style_emoticons/default/smile.gif) Here is some food for thought:

Based on your combo - basically a stock 2.0 think of it this way. All the engines ;1.7,1.8,2.0 use the same camshaft, with the only real diff in basic head design, valve size, l-jet vs. d-jet and the obvious of displacement.

The basic differences, how very very small they are in overall parameters try to look at it this way:

My original 1.7 euro spec with dual 1 bbl carbs made almost as much power as a 2.0 with l-jet; caveat:ALMOST AS MUCH...

My present combo is still 1.7 but with 2 steps up scat c-120 cam, almost 10:1 compression (mathematically calculated but really more near an actual 6.5:1), dual web 40's and the 2 liter stock exhaust with heat removed and a crane ignitor -

I have found the best overall compromise of power / heat produced / fuel mileage is STILL with STOCK web 40 specs: 28mm vents - 45 idles -115 mains - and f7 tubes although I do use better velocity stacks.

I reason the reason this is wholly due to me re-using the original pop-up pistons and cylinders (worn-out) due to running out of liquidity for real ones. So there is much blow-by but darned she still runs strong!!! (IMG:style_emoticons/default/blink.gif)

So what I suggest is starting from the ground-up with the absolute basic set-up. I am convinced you will get more power and better mileage by going down on your mains AND the idle jets as well as returning to smaller vents BUT with using the CB tall manifolds if not already. It may run a little cooler with the extra fuel being introduced as it is now, but with a stock engine set-up, get it more to the stoichiometric side (lean but not really lean, I hope you get what I am describing)

It is quick and simple procedure and also take the time to truly dial in your timing - an aircooled engine with high miles likes more timing than book spec to help make up for loose tolerances and compression loss from excessive blow-by. This is where mech hone their 'tuning' skills. Forget the timing light get the engine up to max hot and ever so slightly advance the dizzy until you get the most minor of knocking (go EASY) THEN get out the timing light and reduce by 4-8 degrees. You will have to guess because I venture when you finally get it to knock you will be amazed how far advanced the timing may be.

My combo sees 48 degreesin SoFl summers and as much as 55 in cold of winter!!! But that is changing soon...New P/c are on order!! I have a-lot of blowby and overall loss of compression, so by igniting the mixture sooner I 'fudge' the power curve.. (IMG:style_emoticons/default/rolleyes.gif)