My friend has a 1987 90 horse mariner that won't run past 2500 rpm. Starts and idles ok but won't run at full power. It doesn't stop it just creeps along at wot. A mechanic told him that he needed a power pack, a stator and a rectifier. Does this sound right? He wanted to charge him $1200 for parts and labor. Is there anything else we should check. The compression checked out good on all cylinders and there is fresh gas in the tank with some sea foam added in it.