Bumping this thread because it has been the most useful thread ever for me in the history of owning my REPU. After years of just accepting that I would always have a horrible hesitation I finally picked up a set of F3 emulsion tubes and put them in this weekend. REPU runs better that ever, especially at cruise. I've never had a perfectly smooth cruise but now I do. I think a little timing adjustment to wake up the top end and I'll be set.
Thank you for starting this thread almost 10 years ago Hyper4mance2k.

Everybody with a Weber needs to be reminded of this thread.

 

Yes, This is a good thread it I am trying to start tuning my 51 IDA on a 13b s4 Semi PP.

Some good info in here to get some ideas,

 

hello, i need some help, i bough a weber 45 for my rx7, now the only thing the engine has done is overlap, i installed it but the guy i got it from is in Ohio, im in Florida, its way too rich, can anyone help me with the size of the main jet, air corrector and emulsion tube? thank you

 

Here is what I have in my EMPI 51MM carb with 44MM chokes on an 1985 Street Ported 13B. Basically this is a Weber 48 IDA made in China for EMPI. For what it is worth I ran the same jetting with 42mm chokes.

195 Main Jets
120 Air Corrector Jets
F7 Emulsion tubes
60 Idle jets
Fuel pressure 3.5PSI
EGT Temps are 1500-1550F measured 6" from the port on the dyno and on the track

Remember that you can change the mixture by changing either the Main Jet or the Air Corrector Jet. Increasing the Air Corrector leans out the mixture while increasing the Main makes the mixture richer.