Mercruiser 4.3 alpha One 1994 shutt down

[mens]

Good afternoon....my mechanic drain about 16 galon of gasoline and it sounds like and it seems homogeneous with no water,but before doing a trip i take off the filter and kept the líquid, and doesn't seem "Pure" gasoline..somehow i put some 2 years gasoline in the tank,about 4 galon..i have change fuel filter earlier becauase of it, and it had some water on it...in adiction the boat was full of gas and before he drains tank i spent about 8 galons,meaning a total of about 24 galons..what is the tank capacity of Mariah 1996 z 190 shabah?it os possible that is still fuel/water in the tank,even that we drain it throw gasoline filter?boat ran great full throttle mas sometimes he dies,.if it was a malfunction in electric fuel Pump (bought 2 months from amazon) shouldn't always give an instable ride?pump is new and i don't really bother to buy an original One,since i have fully sure that the problem came from it.Considering that the fuel is ok, the boat made for 3/4 times a contínuous noise when given to ignition and then it runs,i read that can be oil pressure and other,fluids seemed ok, and now that i'm thinkink itnl only happens when i made trips of 20/30 minutes or more!!!when it stucks i filled de gasoline filter manually and restarted with now Isaura..can anyone help? Oil pressure 40 psi..many thanks