is something missing here?

[mogfisher]

Looking at the carb, it seems to my untrained eye that there is something missing from the left hole above the intake opening. There is an adjustment screw in the right hole but the left hole is just threaded and empty. I dont have a manual yet but I am getting one very soon. Probably order one tomorrow if I cant find one locally. This is on a 1983 18 horse mercury. What adjustment does the right screw make? Just curious. Thanks a bunch.

 

[walleye1968]

Re: is something missing here?

the right is idle mixture
left not used

 

[CharlieB]

Re: is something missing here?

That carb may have been also used in another application, with the left hole used to hold the airbox on.

 

[mogfisher]

Re: is something missing here?

Cool. Thanks for the info fellas. On the idle mix screw, does it just control how much air bypasses the throttle plate for idle speed? Or does it effect the actual amout of fuel injected into the carb too? I'm used to EFI systems mostly on cars so carbs on boats is new territory for me but I'm learning!