1970 Evinrude Ski-Twin, Ski-Twin Electric 33 HP Service Manual 4687, Page 18Get this manual
bInspect the inlet needle valve for grooves nicks or scratchesIf any are foundreplace assemblySee Figure 3-11Gum or varnish on the needle valve must be removed with OMC Accessory Engine CleanerDO NOT attempt to alter the shape of the needle valvecCheck the needle valve seat with magnifying glass; if seat is nicked, scratched, or worn out-ofround, it will not give satisfactory serviceSee Figure 3-12The valve seat and needle are matched set; if either is worn, both parts must be replacedUse new gasket when installing the needle seat W OI{ N