1975 mercury 650 carburator information?

[ShoestringMariner]

Does anyone know where I could get some information on the carbs on my motor? I bought a Seloc motor manual which is 90% junk. It covers 4 carbs across varying years and model sizes, but apparently nothing for the 650.

I would like to set the high low speed back to factory specs. I know which screw is for the idol but I don’t know which is high or low for the jets.

 

[Chris1956]

Crowleymarine shows it to be a sidebowl carb. There should be 1 idle mixture screw on each carb. Initial setting is probably 1-1/2 turns open from light seating.

Normally the distributor opens the carbs. The relationship between the distributor and carb sets the idle pickup timing.

A factory service manual would be your friend.