hi everyone, my 1989 mercury 20 hp is giving me a hard time. It starts fine , idles fine but as soon as i get to 3/4 to full throttle it starts to "sputter" i guess you could say it starts shaking and stalls the power but as soon as i bring the throttle back to halfway it runs fine again. Changed the gas hose and the tank and adapters but still does it. Your help would so much appreciated.Thank you
