I have recently purchased a 2001 Mercury Outboard, 5 hp, Model: ME 5 M, serial # 06971938. The motor is in excellent condition as it had been barely used by the original owner. It starts and will run at high speeds but stalls immediately when throttle is moved back to the lower range. Ive tried adjusting the slow speed mixture adjustment screw and seems to have no effect at any position. <br /><br />Any suggestions as to next step?