carb trouble

[LYNCHSTAR]

hi guys im having carb bother again built a carb last week standard venturi 1.2mm main jet 1mm 1st stage 1.2mm 2nd stage 1mm a/c 1.7mm needle valve. set boost 21psi. car drove fine but on boost it was running at 10.8 a bit rich. left it for a couple of days till my new drill bits came. drilled the a/c to 1.1mm to lean it of a bit the car drives fine but on boost this time its running very lean on boost at 14.9. so i changed the a/c back to 1mm drove it again and its still lean at high 14,s again on boost. this all started when i changed my dizzy cap to a 90deg one leads are on correct surely this cant be anything to do with it surely. any ideas guys.:cry:

[juha5gtt]

First post!

Hi!

I think 2nd stage 1.2mm and 1.7mm needle are quite small ones..if i remember most people use at least 1.3-1.4mm 2nd stage and 2mm needle with 20+ psi. Also upgrated fuel pump is must. Someone else correct me, if i'm wrong.

[Tony Walker]

First post!

Hi!

I think 2nd stage 1.2mm and 1.7mm needle are quite small ones..if i remember most people use at least 1.3-1.4mm 2nd stage and 2mm needle with 20+ psi. Also upgrated fuel pump is must. Someone else correct me, if i'm wrong.

:agree: 1.2 2nd stage was lean for me on an old tired engine at 18psi.