I just purchased two waverunners at a (i thought at the time ) steal ,...the guy i bought them from said he fired them up 3 months ago.They are a little sun faded but look pretty good , well good went wrong when i charged the batteries drained gas tank,added non ethy fuel and put fresh in,brand new plugs and all they do is turn over no start. I did try putting fuel in spark plugs and it starts up and purrs like kitten until the fuel burns off then back to just turning over. So i've come to conclusion it could be fuel filter or pump,..my question is how do i test this theory? thanks in advance for your help