idle problems

[daveeeeee]

I cant get these webers to idle rite! i've been at it all day, they are running ok just very rich atm, but they just wont hold a consistant idle speed, any ideas?

 

[frank]

daveeeeee

there,s sure to be an idle mixture screw ?, 1 1/2 turns out is the usual starting point, then check the plug colours

 

[daveeeeee]

oh yeh ive been adjusting the idle all day but its just not rite, its strange it will either idle way to low or cut out, or will idle too high idle at about 2000revs, i cant get it to sit any where between 0-1500 revs? im stumped

 

[frank]

daveeeeee

are they a 2 x twinchoke downdraft setup ?

 

[daveeeeee]

yes i believe so

 

[frank]

daveeeeee

then i would balance the carbs with a hose in my ear first, then set the idle mixture screws at 1 1/2 turns out, then leave it ticking over for 5 or 10 mins, and then check the plug colours.
if one pair of plugs is sooty, then screw it leaner

 

[daveeeeee]

will give it a try, they are currently jetted to an ma12 whereas im running them on the ma10 so they need a good tuning

 

[curtis]

will give it a try, they are currently jetted to an ma12 whereas im running them on the ma10 so they need a good tuning

They do need a tune...was ment to get to it, i had them re-jetted to the ma10, but then back to the ma12 when i stuck the other engine in

When i took the head off the ma12 engine to re-build i did notice that the drivers side of the head (no. 1,2) Had pre-detonation all over it...

So my guess was that that weber needed a tune, and i had a fiddle with the idle and got it bang on...even with the lights on it ran good, only ever peaking at 1200 and never below 900

 

[daveeeeee]

ok, i've managed to get the webers idling rite but as soon as i turn the lights on or my sound system it just dies, now is there anyone that can educate me on the webers as i'm still learning with them, i've heard that webers have a 'fast' idle, so if you rev the engine, it will stay at say 1500-2000 for ten seconds or so then drop? anyone know if this applies with the dcnf's?

 

[curtis]

Yeah they did that for me...You will see the other screw bit thats on by the throttle cable...turn that to set the idle...

 

[frank]

you will get this problem with any setup with no idle control system, i removed all the solenoids and the fast idle waxstat from my 1.6 t/b, and fitted a valve on the dash connected to a vacuum pipe on the manifold.
it means i can alter the idle from stall to 1500rpm and also adjust the a/f ratio/mixture of the gas while cruising