Weber float level

[2.7RACER]

Four days ago I was getting my 2.7 with Weber's ready for the track this weekend, when I noticed the idle was rough. traced it down to number 6. Number 5 cylinder wasn't much better.
Spark was fine so I removed the carbs and began looking for a plugged jet or whatever. Things all looked good, cleaned everything anyway. Reinstalled the carbs and same problem.
To make a long story a little shorter by day three the carbs were winning this little battle. Just to be sure I had a carb problem I installed the carbs in reverse position, right carb on the left and left carb on the right side. Sure enough the problem followed the carb. Now number one cylinder was dead.
Got me an inspection mirror and looked down the carb throat and noticed at idle the offending carb that fed number 6 cylinder was wet with fuel dripping onto the butterfly, number 5 too. The other four throats were dry on top of the butterfly.
Now after three days the light finally came on in my confused brain. Float level!! Sure enough reset the float a little lower ( about .030"). Start up the motor, look inside the carb throat and now 5 and 6 aren't wet with dripping fuel. Went through the normal set up for idle mixture and all is well.
The lesson? I didn't use the weber fixture to set the floats. Yes I measured and measured but I still missed it.
If I had PMO's I would have noticed a high float level through the sight glass.
After three days I got to know these Weber's very well and I like them more than ever. Simple carbs once I figured them out.

[jclotz]

Also consider that sometimes the floats develop a leak. This problem drove me nuts for a week or two - thinking I had the level set, then seeing gradually more and more fuel collect in the throat after shut-off. I tried to seal the leak but after several attemtps gave up and bought a new one.

[Fishcop]

And when all else fails, don't hesitate to change the needles... every now and then one may go bad (I got a crap one from new once).