Are you turning the carbs upside down to adjust the floats? That is on the SU video from ztherapy but it doesn't work with the valves you buy nowadays. They were using Grose valves in that video. Those are built different and would not hold the weight of the floats while setting the gap between the float and the lid of the float chamber. The newer needle valves will not hold the floats up. I fought with this for a long time then made my own "float chamber" out of a clear glass jar and set them that way. That's been about 10 years ago and I haven't had to touch them since. They run great. I got rid of the lid with long ears and use two short ear lids essentially turning them from 3 screw carbs '71-'72 to early four screw carbs '70-'71.

Edited Thursday at 10:14 AM4 days by siteunseen

9 hours ago, emptech said:

I like the idea of using a brass screw, either off the shelf or fabricated. I have a lathe, so I can fabricate the screws. What did the screws end up weighing?

Last time I messed with this, I tried to use off the shelf screws and I could not get enough mass packed into a small enough package. I've found that 4 grams is a good amount of mass to get the float to sit level at equilibrium, and the wood screw just didn't weigh enough.

Here's a failed attempt to use a brass wood screw instead of making my own weights from scratch. Pic of a wood screw chucked up in the lathe, narrowing the head, The process of narrowing the head worked fine, but the amount of mass remaining wasn't enough. I ended up making another pair of weights from scratch.

Here's a pic of what didn't work out:

I decided to go through all 14 pages of this thread. I spent many hours trying to get my fuel level in the bowl correct, whatever "correct" is. I even fabricated a plexiglass model of the fuel bowl so I could actually test the float in combination with the needle valves, which I know are NOT grose valves. I also found I was totally wasting my time by measuring the distance from the top lid of the fuel bowl to the top of the float, which we now believe was meant for grose valves. The critical measurement I've learned is the actual fuel level in the nozzle, not the bowl. Either .426" or 10mm would be the level of fuel below the carburetor bridge. That level happens to be based on the fuel level in the bowl, which is determined by how one bends the tabs on the float itself. Some of us have discovered that to get the proper fuel level, the float is actually too high in the bowl and is dangerously approaching the lid of the float bowl.

As you can see, CO has fabricated some brass screws that when inserted into the float will help the float attain the proper angle when the fuel level is correct. I have fabricated similar screws and will drill and tap holes in the float as CO did, and hopefully after re-adjusting the tabs will finally have the proper level.

I will report back with my findings, but from I've read from CO, I am expecting good results.

Jim

I've read that the mixture screws raise or lower the nozzles 1mm per revolution. One can raise the nozzles to the top and lower them 10 turns. At ten turns, the fuel level should be near the top of the nozzles.