1964 75 horse evinrude can't pin down problem

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i will start with what is happening motor goes through 6 gallons of gas in just over one hour seems excessive to me but when i had it out and running two weeks ago it didn't go through that much gas. next it ran good two weeks ago next time i took it out it would not get up to speed and would surge unless at full open but was running at 2/3 speed. so i went through the carb on it because it had a wet gasket in one corner. i added new float and valve and seat and gasket kit. the carb was clean and i think was rebuilt resonantly i also checked compression it had about 80 psi give or take 2 psi per cylinder. and new spark plugs i went out this weekend and it started good i ran it seemed to run well but still a little slow but smooth all through the throttle i shut it down and sat for awhile and tried to start it did not want to start sputters and quit finally it starts but had to give it gas and rivet up. but now it surges and at full throttle it is slow. i have rebuilt the fuel pump the carb, points cleaned the motor new fuel lines , vacuum lines plugs but there is the one common occurrence the number 2 and 4 plugs are all ways oily and wet on the old plugs and the new plugs i have checked the spark and it seems fine. i'm thinking valves ? i dont know what else to check