2 stroke oil reserve tank over filling with fuel ???

[No more boats]

2000 OX 66 =250 hp - 2 stroke
yesterday , pulled boat , pulled drain plug
water coming out was clear , then oil was mixing with the water with a smell of gas coming out ?
Never had a problem with 2 stroke oil system

gas is returning & over filling 2 stroke external reservoir . ( reason for oil/ fuel in bilge ) tank was overfilled with oil & fuel coming from top and where tank is mounted it runs off into bilge
Engine oil tank had gas mixing also
Making a complete loop of the oil system
realize i can run 50 :1 oil mixture by passing but want everything working as it should
what would cause the fuel too come back too oil reserve then fill engine oil tank ?
oil pump ?
inside vst tank ? stuck float
check valve ?
this issue must have happened on return too port cause hour earlier my head was in bilge and everything was fine , I was off shore close too port

some thoughts is appreciated

 

[99yam40]

I have no idea how gas could be transfered to the oil system in an injected motor

 

[No more boats]

I agree with you ,
I have a retired marine mechanic buddy , he looked at it yesterday ,
He said this is a first ,
He feels its the check valve causing back flow ???
He said if you cant fix it , just by pass and run 50:1 directly , as a last resort but want it running as it should