Re: needle ajustment on carb
Steve, I've been looking closely at the carburetor diagram for the 3.3 Evinrude (
http://www.ishopmarine.com/ishop/js...~A0000022~M0015034~M0015044~M0015045~C0306274) you referred to in your earlier post regarding this problem. It appears that items #21 and #22 in that diagram control the gross idle speed adjustment only. It also looks like you have 2 fixed needle jets (#8 & #10 in that diagram) and a fixed main jet (#16 in that diagram) that control your gross fuel mixture, as well as a mixture control needle (#19) and seat (#20) that may allow some degree of adjustment of (presumably) the low speed mixture. This carburetor appears to be somewhat similar to the smaller Tecumseh and Honda 4-cycle small engine carburetors that draw fuel from a bottom mounted bowl thru a main jet. This carburetor also appears to be identical to those mounted on similar Mercury Mariner and Yamaha motors. In reading posts regarding those outboard motors, rust in the fuel tank seems to be a problem in that it then tends to flow to the sediment bowl and then clog the main jet (#16) and lower needle valve (#10, which may also have several emulsifier ports on its upper end). This is also a common problem on smaller Tecumseh and Honda engines, with which I have some experience. Usually this jet/needle assembly is removable, although some posts in the Mariner/Yamaha forums indicate that it is fragile and must be handled with care. I think this assembly is what you must remove and clean thoroughly before you can expect to get much further with this problem. And yes, the external mixture needle/seat assembly (#19 & #20) should probably not be screwed completely down, but I am clueless as to the recommended setting and none of the Mariner/Yamaha posts offer any advice in this regard. Try screwing the needle/seat assembly out about 1 1/2 turns and see what happens. Good luck.<br /><br />John
