Setting Low acceleration needle valves?

ZZiippyy Wings

Recruit
Joined
Aug 2, 2002
Messages
1
I have a 1975 Johson, 50hp, two cylinder. It has two low acceleration needle valves. I obtained the manual but it does not inform on how to set them. Any info would be greatly appreciated.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: Setting Low acceleration needle valves?

Tessler.... Perform the following on the top carb, then the bottom carb.<br />(Carburetor Adjustment - Single S/S Adjustable Needle Valve)<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. 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.
 
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