AeroInjector-Mixture Arm Position

[Area 51%]

Was on page 13 of the injector installation manual setting up the mixture cable. Knob full in, cable housing distance set, arm at 45deg. Snugged everything up.

Pulled the knob out to check the clearance between the arm and cable housing; found there was none. Moved the housing aft 1/4in and repeated the cable-throw test. Again, no clearance at the housing. Rinse....repeat; still no clearance between the arm and housing. I do now, however, have about a 70deg angle on the arm at the full rich position.

What was happening was the arm was slipping on the mixture shaft, rotating it forever clockwise in relation to the shaft. Didn't even cross my mind to check it's tightness. It was snug enough that it didn't move while I was handling it.

The problem now is, I have no starting point/angle to align the arm to the shaft in the cutoff position. If the arm is set one way or another from it's proper orientation, and the control is pushed it to the full rich position, it could be leaner or richer than it should be.

What's really needed is the total angle the shaft should rotate from cutoff to full rich.

Question: Does the mixture continue to richen after the 45deg is reached? If it does, that might explain why some injectors run extra rich at the full rich position. It might have nothing to do with the needle.

[sonex1566]

It's basically just a fuel tap. If you rotate the shaft to the fully closed position and have the arm at 45 degrees it should be about right. Moving the mixture lever doesn't make any difference at first, especially at low throttle settings. My engine runs super rich when the throttle goes from around 7/8's or so to wide open. I have fluffed around endlessly fiddling with settings and discovered no difference to power output if tuned at WOT or 7/8's. My theory is that the fuel isn't atomizing properly due to no venturi effect. Funnily enough if I'd read the instructions properly I would have saved a lot of time. The mixture control is crude, but it works. The Rotec and Ellison injectors work differently and appear to be more fancy, but they all do the same job. Good luck.