Weber IDA + 3.3 Grose Jet = how do I set the floats?
 

48 IDA. 3.3 Grose Jet with the glass balls. Does anyone have a solid float level setting for street use? 13b streetport. Like how far down into the bowl the top of the fuel should be?

If my fuel pressure goes above 3.0 psi the engine stutters, spits, and runs in the 11.0-11.8 AFR range on light throttle cruise. If I lower the fuel pressure to 2.5 then it's in the low 12's but still stutters some. But when I come to a stop the idle starts off at 13.5 and slowly creeps down to 12.5 and is erratic.. This tells me it's a fuel delivery problem.

The top of the fuel in the float bowl, with float installed was 10.50mm from the top of the air-horn gasket. I increased that to 10.89mm and will see how it goes. But any input is recommended.

Another question is, what is preferred. A low float with high fuel pressure, or a high float with low fuel pressure?

I would think a low float level, and high pressure. Specially if you're running Grose Jets.

It's all a matter of where the holes are on your E tubes. Measure the height of them to make sure the right ones are drawing air and the right ones are drawing fuel.

How does the 3.3 Grose Jet compare with the standard Weber needle valve size range? A 300 will feed anything a street port needs. You should be able to run fuel at 4.5psi with no problem, it sounds like you need to drop the fuel level quite a bit.

i set my float the stupid way. i took the air cleaner off and looked down there, and lowered the float until the boosters stopped dripping.

plan B was to remove the plug on the float bowl and replace it with an 81+ brake bleeder screw and some clear tubing. it the method in the comp book, i found it really tricky

plan C might be to make a stick with measurements, and use the vent hole on top.

so i lowered it until the booster stopped dripping, and my mixtures are consistent now, but ive ended up with jetting that's probably leaner than yours, so i tried to lower the float more, and car no run (!)

i'm running a carter pump, no regulator. i tested the pump with the car off, and it only did 4psi, and free flow volume sucked, but it may be that it does more with the engine running.

jgrewe is right as well.

From my understanding, and what happened to my car, the gross jets like higher fuel pressure and you've got to run a system with a return. With the gross jet installed if you hold the carb upside down the top of the float should extend from the float bowl no less than 5.5mm and no more than 6mm. Gene Berg sells a little kit to do this with.