hi everyone, i have a 1989 Mercury 20hp on my 14' sylvan . Carburetor kit was done , spark plugs also etc... The motor runs fine at idle and 3/4 throttle but as soon as the motor goes full throttle it starts to shake a lot , cough, jerk and spurs and it loses speed but as soon as i bring the throttle at 3/4 it works fine....is it cavitating? is it the high speed jets?? i would really apreciate the help...Thank you..The problem was there before i had the carburetor done(i thought it would fix the problem but it didnt)
