zenairdave
Registered User
Ontario
I assume that you have this: http://wiki.ad7zj.net/wiki/images/8...ce_Manual_Models_MA3A_MA3PA_MA3SPA_MA4SPA.pdf
From page 16: "Assure that theaccelerator pump discharge tube is locatedinside the center ring of the venturi"
Service bulletin # MSA-7 dated 10/11/94 covers your situation. There is a kit 666-942 to solve the issue and it appears that your carb has had this kit installed which is the installation of the 47-850 nozzle.
I'm unable to locate the diameter of the jet openings.
If I were you I would pick up the phone and dial:
Yes, the accelerator discharge tube is located inside the venturi but it really did not make any difference. Don't ask how I know.
Good advice on phoning and I called them. Tech support was very helpful. It seems they start with a .0935" jet in the pepper box nozzle and when they flow test each rebuild, they drill as needed to achieve the "spec" flow. I will be a while before I can measure the existing jet but it follows that a new one will likely be the smallest they would ever expect to use. Since these tubes are about $250 in Canada, I hope to not have to try too many times. Since I also have no cut off rise, the carb guys really recommended that I get a rebuilt carb which should fix all my problems. My thinking is though that there are too many threads that say the new carb owners got was so rich that their motors did not run well. That is exactly where I am at, at full throttle position so don't see the value in doing a new/rebuilt carb.:sad: