I just had a serpentine belt kit installed to my
Yanmar 3YM to alleviate belt breakage and dust problems. All is working great except for the fact that the rev counter is now reading well high. What used to be 2500
rpm is now reading as 3400
rpm (based on SOG - I dont have a digital tachometer). The
alternator is about 3 years old. Its not genuine
Yanmar, rather a Hitachi 80Ah.
What could be causing this and how might it be rectified?