CNYRX7tech

Everyone/Anyone,

I have a sweet 80 Fb at my shop and need help ID'ing the twin weber? carbs. I am chasing a rich idle which is causing a hard start. I have yet to check any of the basics but what i know is that the 12a has headers, twin carbs and a dial fuel pressure regulator. Any ID point would be very helpful

nimrodTT

do they look like this?

CNYRX7tech

same intake, but fuel inlets are on the other side. they appear to be of a weber design.

nimrodTT

So are just the filters the same or what? Though there may exist another carb that fits this manifold, I do not know of one.

CNYRX7tech

yes, K&N filters are the same. oil injector lines same locations. but different pressure regulator.

BadAssRX-7

thats a r.e. 36 dcd set up... i was about to post pics of mine but oh well

nimrodTT

Rich idle will mostlikey be the result of the setting on the mixture screws at the base of the carbs. Start with 2 turns out and play with it untill you get the smoothest, highest idle possible (mine were always at 2.5 on a stockport motor). Then back down the idle speed adjusters to where you want it.

By the way, the webers take in way too much fuel for that purolator to keep up with, the guy would be better off without any regulator, or you can get him a holley regulator (~$20) that will work much better.

hanman

By the way, if it is an 80 it is a SC not an FB.
another useless bit of trivia.
hanman

CNYRX7tech

ALrighty, Basics have been checked. Compression is 95 PSI per chamber.idle vacuum is bouncing from 15 to 20. Fuel pressure looks to be under 4psi and pressure regulator doesn't make any difference with the pressure. The pic above is the same set up with different regulator.

nimrodTT

Is the idle vacuum bouncing while the engine stays constant? And that fuel pressure needs to be at 4.5psi

peejay

Overrich will cause the idle to fluctuate... my streetport wasn't happy when it was adjusted lean enough to idle smoothly. It would bog a bit when you went to accelerate, and it liked to stall when you let off suddenly. In other words, didn't really generate enough vacuum to idle consistently at 750. i could have just raised idle speed to about 1100-1200, but instead I just richened the idle mix and let it lope

CNYRX7tech

Badassrx7 and NimrodTT takes for the ID help. Turns out your both right Found front rotor card leaking fuel at idle out of the seconary.