Idle air adjustment screw location 1983 Evinrude 75

[anderso8623]

Title says it all, where is my idle adjustment screw on a 1983 75hp Evinrude.

 

[emdsapmgr]

Your carbs have three fixed jets on each carb. Usually three fixed jets includes one of them which is the idle air bleed. You carb has an additional brass screw toward the top of the front of the carb. This screw is adjustable and probably will make a difference in the idle if you fiddle with it. You will want to refer to your factory manual regarding the idle adjustment. I've got a later 3 cyl, and on mine, as you adjust one carb, it actually also messes with the carb idle setting on the other two at the same time-through the manifold. I labor over the factory manual and still feel my adjustment is not optimal Which means you adjust slightly, wait 30 seconds to see what change occurs, then make another slight adjustment. Back and forth between carbs-a real tedious adjustment.

 

[anderso8623]

Is it the screw just below the word spark? If so, that is a jet.




Here is the starboard side view



Here is the port side

 

[anderso8623]

I found this on evinrude a website. Would it be the needle valve behind the jet?

 

[anderso8623]

I called the local shop and he said to disconnect the choke linkage and one by one tap shut the butterfly. If the rpm goes up that's the carb causing the problem, if it Boggs down the carb is good. The lower two are good, the top was the one causing the problem. He also mentions that with that year, there were two types of carbs, one with the needle valve and the other with the fixed jet. I have the one with a fixed jet and it is not adjustable. he told me to tear down the card again and re clean. After the tear down, when I repeated the test the card bogged down instead of revving. I adjusted the idle stop to a lower rpm and once warm it holds at 800 ish RPM. I say ish because it's an analog tach with increments of 200. It floats right at the 800 mark but does drop a little lower. I am going to bring the carbs in after my trip and have him sonic clean them.