I've got a brand new Weber 38/38 on my B20E that has a header, elec. ign and slightly overbored cylinders - all else stock.

Right out of the box, this thing works WAY better than the two 32/36 carbs I'd tried. However, it still has a NASTY stumble (car seems to literally shut off) upon initial throttle input - particularly from very low RPM's. Once the rev's are up, the engine seems to perform pretty well, but this stumble is bad enough to render the car almost undrivable.


Does anyone have any experience with this carb on a similar engine? If so, could you share your optimal config regarding jets/tubes/air-correctors etc?


Aside from a sparkplug wrench, I don't have any equipment to help determine the A/F ratio - so I'm really not sure if the engine is going rich or lean during the stumble. The plugs are a bit black looking, but I'm not sure if the blackness is from the higher RPM driving or if it is a result of the stumbling.

FYI: The current jets are 140/140 and I've tried 45/45 and 55/55 idles. I think the air correctors are either 160/160 or 170/170 (i forget) and the e-tubes are 50's.



Any Help Would be GREATLY appreciated! Many Thanks!