EvinRude 74 Model 25 HP Air Mixture screw?

[Crappie_Fan]

I took the boat out this morning after not running in awhile, I ran kinda spurterish, When I would full throttle it would surge like it wanted to go. So I change spark plugs and still same thing, so I came home and cleaned carb. Unfortunatly I forgot how many turn the Rich/Lean screw is from fully seated position Maybe someone knows how many turns it is?<br /><br />Thanks

 

[Paul Moir]

Re: EvinRude 74 Model 25 HP Air Mixture screw?

1 and 1/2 turns counter clockwise from lightly seated. If you turned it down hard, it may be damaged.<br /><br />Good luck!

 

[Joe Reeves]

Re: EvinRude 74 Model 25 HP Air Mixture screw?

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)<br />(J. Reeves)<br /><br />Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.<br /><br />Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.<br /> <br />Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting. <br /><br />When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.