Evinrude 150 FITCH

[Acteam]

150 hp FITCH runs great except between 3,000-3,500 rpm. In that range motor acts and sounds like it's "missing"..........I get a fast, constant, very deep-sounding "whup-whup-whup"......outside these rpms it goes away. New plugs didn't help.
Any ideas?
Thank you!

[Acteam]

[QUOTE=Acteam;5726]150 hp FITCH runs great except between 3,000-3,500 rpm. In that range motor acts and sounds like it's "missing"..........I get a fast, constant, very deep-sounding "whup-whup-whup"......outside these rpms it goes away. New plugs didn't help.
Any ideas?
Thank you!