MG MGB and MGB GT Tech Talk
Hello All,
This is a long shot but does anyone know the default (shipped) jet size of the Weber 45MCHH? I bought mine used and it came with a sleeve of different sized jets (most missing) and as the carb is a little heavy on gas I was wondering if anyone knew what the default jet size is supposed to be.?
Thanks much, John
John -- I bought mine new from Weber Direct, but there was nothing in the accompanying paperwork that mentioned jet size. I just checked.
Chuck
Thanks chuck - worth a shot. BTW - whats the MPG on your car?
Thanks, John
I read on another forum that the 45 mchh comes with a #40 idle jet, the guy contacted Weber Direct and got a #45 and a #50 sent to him. Installed the #50 and apparently solveed his problem.
I have a question that might sound a bit silly, but which screw is the idle screw and which screw is the mixture screw on these carbs?
Thanks for that. AFAIK there is ONLY an idle mixture screw - the one that is visible on top of the carb. Any other adjustments is all via swapping out jets.
Thanks again, John
lewk Wrote:
Thanks John, but what is the screw above the throttle "wheel"?
The Weber 45MCHH comes with a #40 Idle jet. If the carb idles rough, and backing the idle screw out has little affect on it, then it may need a new idle jet. Call the Weber support number and they'll send you a #45 and a #50 jet. They are very easy to install. Just remove the coin sized cover on top of the carb, then remove the slotted jet holder (not the one with the hole in the middle) and pull out the old jet. Next, place the new jet into the holder and screw it back in. Now replace the cover and that's it. With the right jet, you should get a good idle with the idle mixture set at about 2.5 turns out. The MCHH is a great carb once you get it set up. I really like mine.
The Weber 45MCHH comes with a #40 Idle jet. If the carb idles rough, and backing the idle screw out has little affect on it, then it may need a new idle jet. Call the Weber support number and they'll send you a #45 and a #50 jet. They are very easy to install.
I also installed a 45MCHH on a 1980 B. After installing new motor mounts I was no longer able to fit the air cleaner and had to resort to a cut down stack (only 1 1/2" exposed). I tried many different motor mount shim combinations but couldn't align it any better, and even now the top of the carb is within 3/8" of the MC.
Original jet sizes installed in mine were:
idle: 40, however I had to replace with a 50
main: 170 - my car runs extremely rich and I'm waiting for delivery of a smaller jet
air correction: 160
After many years of trial and error, I wound up using .55 idle jets and .170 mains. I found that the 3.5 auxiliary venturis worked best with my application. Your results may vary. RAY
Ray,
Are you by chance talking about a 45 DCOE as oppossed to a 45MCCH?
Joe
Try Midwest-bayless.com
They have an entire weber parts section for jets and little pieces like that. Its all stock stuff..
If you need any further help, call Weber themselves! 631-863-2036. The carburator guy leaves around 430.