20 hp Merc (1978?). Serial No 5292553. <br /><br />50:1 fuel mix? <br /><br />I tried 50:1 and motor won't stay running. "Coughs" and "wheezes" then sputters out. <br /><br />Thinned out fuel a bit to approx 35:1 and same thing. Do I need new plugs now? Is the carb shot? <br /><br />Thank you!!!
