suspected lean fuel condition

[bobsdats]

sorry to intrude, but, how do you set the float level in a r-16, hitach carbs, with the newer metal encased plastic, free floating floats ?
i set the metal lever piece at 12mm from float chamber top. after warm up, the engine idles fine(2 turns down on mixture), but back fires and
starves trying to rev. i can pull out choke and revs ok then, so carbs are lean. how close to the top of the moveable jet should the fuel be?
ive done a ton of the carbs with the brass and solid plastic floats. my first time using the metal encased plastic free standing floats.

[bobsdats]

appreciate input. will ck back later, so no quick reply.

[redroadster]

Yes a completely cold compression test , easy to do or a leak down .
How sure are you the coolant is flowing vg ? A infrared meter/ tester pointed on the header pipes is a good diag tool, did you try carb spray on the intake for a vac leak possible the sollex slide isn't rising the same on the rear ,? did you try new spark plugs on 3 &4 ? fuel fowling does nearly the same and plug threads clean ?
Try retarding the timing slightly to see if the disruptive running quits
You think you have a problem , but usually there's 2 or 3

[bobsdats]

i tried raisingthe float levels again, no help. like i said, it idles fine once warmed up. just wont take the gas, so to speak. im going to ck the moveable jet and the hose connecting to the float chamber for partial obstruction. then measure the mixture needles along the taper, against an old set
of r-16 1600 hitach. needles. this car was doing this problem when i got it to work on(not mine). ill try some of redroadsters ideas, too.
sometimes i skip the simpliest things. ive been working on these roadsters for 50+ years.