I am the original owner of this 70 4-stroke Evinrude. For the last few years, have not been able to use the motor that much due to power problems.
First, when I put muffs on the motor and run it, it seems to run fine, but when I actually put the boat in the water, it does not have very much power at all. Ocassionally it would take off with full power only to revert back to a "bogged-down" feel with no power.
I have put it in the shop a couple of times and they never really have been able to identify and problems other than the last time I was told it needed a new fuel pump. Around $800 later, the problem is no better.
Second, I have now noticed that the more the engine is run, the higher the oil level gets. In fact, it seems like gas is getting mixed into the oil.
I am desperate for ideas as t what all I may have going on here. I have no idea where to start....