Page 1 of 1

Help needed setting up idle on carbs.

Posted: 01 Mar 2007, 17:24
by The_blue
It's a CU 2litre engine with standard carbs.

I had it running ok but the CO was off the scale....

I've followed the instructions in the haynes manual but think i've screwed it up as it won't even idle now :(

I started with the idle stabilizer bridged.

Adjusted the idle screw till it ran at about 900 rpm.

Then i played with the bypass idle screw but this didn't do much untill it stalled when screwed right in. so i left it a few turns out.

Next is where i've gone wrong........



I disconected the throttle linkage as stated in haynes

screwed the bacic idle screws in fully on both carbs and opened them again 2 1/2 turns.

Haynes states that the lead should be disconected from the bypass idle cutoff but is this the right carb, the left or both??

Next it says start the engine but it hardly runs now. Infact it won't for more than 5 secs with the cutoff disconected on the right and stalls straight away it unpluged on the left.

the book says turn both screws untill it idles at 500-700 and 3-5% CO. What should i do with the Idle adjusting screw and Bypass idling screw while i'm doing this?

Any hints or walkthroughs would be great!


Thanks in advance :)

Carbs/mixture etc

Posted: 03 Mar 2007, 19:28
by Fritz
Blue,,,,,,,I hate to say it but you may be flogging a dead horse, and your attempt to make it better may have made it worse....

It is a fact that over a period of time and use the throttle spindles on these carbs wear enough to allow air to be drawn in enough to cause general running concerns,,,,eg weak mixture, lumpy idle, flat spots etc, etc
And if the previous owner has had problems in the past, over enthusiastic twiddling of the mixture screw may have taken place in an effort to compensate for worn spindles..... :shock:

First couple of questions must be,,,, did you clean out the carbs before you started ? are you sure the throttle spindles are in a good condition ?

Gasure do a repair service on these carbs, or even a chat with them may help you decide what to do next....

Regards

Fritz,,,,,,,