Mercury 300xs, serial #1E051504 w/ 132 hours.
I just had my grey air injectors cleaned & serviced by a reputable company. (i.e. a company that Don has mentioned he trusts, and fwiw Integrity Injection was my first choice but schedule didn't work out this time around)
The injector service company states that 4 out of 6 injectors are flowing too much (fluid, as they can't measure air) after cleaning, and should not be used. The worst out of spec injectors are flowing about 8% over at idle-midrange, 5% at full throttle.
I had previously read an ongoing debate about whether Optimax Direct Air injectors flowing too much will air lean out an engine, or not. A third injector service company makes this argument in another forum:
If you calculate the volume of air injected into a cylinder per cycle by a direct injector, it is less than 1% of the total combustion air. And a "word on the street number" from Mercury purports the total volume of air ejected into a cylinder per cycle is less than 3%. So using Mercury's number of 3% in a hypothetical example...if a direct air injector is flowing 33% high (out of spec) that's 33% extra air on 3% of total combustion air, so only raises the overall A/F ratio by 1%. He goes on to state that the primary function of the direct injector on Optimax is to atomize and disperse fuel, not to modulate A/F ratio.
I can see both side of this argument on a hypothetical basis....i.e you want air and fuel injectors matched and flowing in the correct ratio. I could also see how the amount of air introduced by the direct inject is actually a small fraction of total combustion air. I just don't have enough real world experience to take a chance on the "slightly out of spec" high flowing air injectors.
Hopefully Don will have time to chime in, but very interested to learn if an air injector flow too slightly too high after cleaning is a problem or not?