webber butterfly bypass?

[Brett240]

Hi guys,

im in a bit of a jam,

ive put on a custom fuel injection system that uses webbers as throttle bodies but i cant get the thing to idle below 1800RPM. even when the butterfly's are closed off it still runs at 1800. is there anything after the butterfly's on webbers where air could be getting in? ive take the fuel needles out as there are now fuel injectors down stream.

[Bruce Woolmore]

I suspect that without any fuel in , your idle circuits could well be bleeding quite a bit of air in. the only needles the webers have are the idle screws, so you could try putting them back and screwing them right down.

you may have to solder the progression holes closed too, but that is getting a bit to close to the point where you might want to sell the webers and buy plain weber-style bodies.

what is the injection system btw? I'm interested in going down the throttle-body road myself!

good luck!

[Brett240]

its a custom system, have a look in my gallery. its been a bit of a pain in the arse but its almost sorted now, the injectors are mounted in the webber manifold.

sorry im actually unfamiliar with the way webbers work as im only using them as throttle bodies,did the idle screws go in before the butterfly's or after?

where are the progression holes? are these in the top of the webber?

[Bruce Woolmore]

the idle screws are on the head side of the throttle plates, right up close to the mounting flanges of the weber.

having thought about it, I think that the progression holes would not affect it, as theyre only open at part-throttle.

but check that the starter circuits (the little levers on the back of the carb) arent part open too, they could let a bit of air thru via their holes upstream of the throttle.

hope that helps.