1989 Yamaha 40hp Jet Oil Leaking Bottom Carb

I Just Bought The Motor And Oil Is Leaking Out Bottom Carb And Blowing Out Exhaust. I Drained 2 Stroke Oil And Disconnected The Ground To The Oil Injection. To Test Motor I Made Up Some Premix And Motor Ran Great. Would I Be Better Off To Just Run Premix Now On Or Have Oil Injection FixED. What Is The Chances Of The Oil Injection Going Out. Thanks

[boats.net]

Could be a seal leaking from backside of oil pump or could have a bad check valves in oil lines.