Stumbling till 3.5k
 

Ok so I have a Streetport 12a with a Mikuni phh44 carb I’ve been having trouble with the carb for some time now when I first bought the car if i jammed the throttle it would fall on its face but as of recently it’s gotten worse all the way though the rev range up until 3.5-4K ish it stumbles and if the car is under load it will bog and die if I’m below 3.5k but after that everything is pretty much good the one way my car is driveable right now is if i hold the choke out while i drive then it acts somewhat normal unless it’s between 2k and 3k then it stumbles a bit if anyone has any ideas they are all welcome i just rebuilt the carb today thinking that would help and it didn’t really help at all it kinda helped when i lowered the fuel pressure but it was marginal at first I thought it was ignition related because I just washed the car but since if the choke is out it’s ok I think it’s carb related
https://cimg0.ibsrv.net/gimg/www.rx7...4662c1bf9.jpeg
https://cimg8.ibsrv.net/gimg/www.rx7...7ada7a7f7.jpeg
https://cimg2.ibsrv.net/gimg/www.rx7...f21b86c54.jpeg
Main float bowl area
https://cimg9.ibsrv.net/gimg/www.rx7...2703d50ec.jpeg
https://cimg6.ibsrv.net/gimg/www.rx7...f34101534.jpeg
These are in the chamber under the accelerator pump

Well...If it runs better with the choke pulled, you're gonna have to richen it up. Look for others rec jetting for the Mikuni.

Double and triple check for a giant vacuum leak. Then check again.

I do not know if you have sovled your carburator mystery, but my Mikuni 44PHH issue was a vaccum leak from the carb / intake manifold mating surface one of the rubber O-rings had given way and air was leaking in bad through the visually unnoticable gap. I should have figured it out much eariler as my carb was making a loud hissing noise.