working on a suzuki king quad, thing would not start so I check spark all good, checked for fuel good to go, then did a compression check and the gauge will jump to about 40 psi then it will fall right back to zero every compression stroke, so I pull the head off and all the valves look good, have not taken them out of the head yet but they look good, spun the motor over and cant find any major scratchs in the cylinder wall. anyone have any ideas?? oh and when I pulled the air box lid off it was about half full of gas never seen that before.