Direct C51
Well-Known Member
I understand the basics of how a carburetor works, but in troubleshooting a problem I am having, I have come across differing opinions.
#1 If a carburetor is correctly jetted, what would happen if the inlet was not big enough?
#2 Conversely, if a carburetor is jetted correctly, can ram air disturb the mixture?
The problem I am having is above 4000' DA or so, at high cruise power (65% - 95% throttle setting), and mixture full rich, the engine runs very rough. The problem is resolved if the engine is leaned via the mixture knob, or at low altitude. The engine also runs well at full throttle. I do not have a ram air inlet at this time, so question #2 is for my understanding only. I'm using a rebuilt MA3-SPA Carburetor. The shop had a run of incorrectly jetted rebuilds, which mine was affected by. It was sent back for rejetting before being installed. The rebuilder claims it is now jetted per the stock specs and was flow tested. I'm suspecting the jetting is still not correct.
#1 If a carburetor is correctly jetted, what would happen if the inlet was not big enough?
#2 Conversely, if a carburetor is jetted correctly, can ram air disturb the mixture?
The problem I am having is above 4000' DA or so, at high cruise power (65% - 95% throttle setting), and mixture full rich, the engine runs very rough. The problem is resolved if the engine is leaned via the mixture knob, or at low altitude. The engine also runs well at full throttle. I do not have a ram air inlet at this time, so question #2 is for my understanding only. I'm using a rebuilt MA3-SPA Carburetor. The shop had a run of incorrectly jetted rebuilds, which mine was affected by. It was sent back for rejetting before being installed. The rebuilder claims it is now jetted per the stock specs and was flow tested. I'm suspecting the jetting is still not correct.
