I am building a locost with a 2.0 dohc engine running twin 45 webers. Finally got it to idle but if I try and hold revs with the throttle pedal, it revs up but then drop off shortly after. Would this maybe be the main jet size being to small?

I'm sure there's some weber experts on here with a simple fix.

Any info welcome.

Cheers guys

It could be the main not starting early enough or it could be the idle ending too early.

What revs does it die at, and can you get past that stage by using the accelerator pump?

Yeah to keep the revs up you have to pump the accelerator but if you try and hold the revs up with the pedal the revs drop off.

Not sure what jets you have in, but there are some useful figures here which could give you a head start to get you rolling.

http://www.emeng.gentlyhosting.co.uk/RollRoad/Rolling_Road.htm

D Andrews
Try this link to Dave Andrews site.