I hate webers Options

[FJ1200]

Good Evening,

Fairly new to the forum, but a long time Porsche/Audi tech. Last spring a bought a very rust free 72 914 with a 2.0L and a side shifter transplant. The engine is fairly fresh and was built by a local guy who still builds approx 40 type 4 bus engines a year. It has a web 86b cam, large valves ported heads and twin 44idf's (i know too big).

So I have chased poor low speed manners since I got it, I rebuilt the carbs and replaced all of the intake gaskets and carb gaskets, no change. So after farting with it yesterday I came to realize that at low speed >2500 rpm it was a little lean. I pulled the idle jets and inspected, they were 60's. So I decided I would open them up to 65's. I borrowed a set of numbered drills from 61-80 and checked them. For more info a 60 jet is .6mm or 0.0246" The results are as follows.

.0210
.0220
.0220
.0245

What the hell! Over a 10% variance over four OE weber jets that have never been messed with. So I drilled them all to 0.0245" cleaned them and reinstalled. Fired up the car and set idle mixture, all four landed at approx 3/4 turns out. The best part is it runs AWESOME! it will pull cleanly from 1000 rpm in 3rd gear, no fluff, just clean and smooth. Idle is rock solid at 850 rpm.

So the moral of the story is, just because the parts in a car may be OE and new does not mean they are "right", I encourage if others have low speed driveability issues with webers, check the idle jets and make sure that they are all the same.

Have a great day,

Dan