40H carbs?

[Schiada]

Cleaning up the carbs on my 40H . Found a drilled hole on the port side,after the throttle plat,about 1/2" behind the last progression hole.Carbs are AJ33A.
It is on both carbs. The amount of dirt on the carbs I never saw it.
This is a direct leak in atmosphere? Is this a "H" thing?or does this need a plug?
Thanks of the help! Can't find anything in the manual!
Randy

Added a photo. Hole is just ahead of the mounting flange.

[Fastjeff57]

Seen that before. I believe its purpose is to raise the idle speed/ air flow rate at closed throttle.

On Merc triples, I've found that enlarging the three, existing holes in the butterfly to 1/8 " makes a HUGE difference in eliminating bogging. The enlargement is not that much, but the effect is impressive! Perhaps that's another reason for that hole?

Jeff

[Schiada]

Thanks Jeff. That is what I was thinking . May have something to do with the H lower unit? Can't seem to find a idle RPS in the manual. Not mush info in the manual for the 40H

[Mark75H]

Doesn't have anything to do with the lower unit.

[Schiada]

I was thinking that Q lower mite need a higher idle? That's all.

[Mark75H]

Nope, generally doesn't. A few years later all racing motors were altered to stop at low idle rather than idle well as a safety measure. I have no idea what the holes are really for or if they would be found on all