Boat seems to be rev limited in Forward but Not Reverse

[Derek0302]

I have a 1965 Penn Yan. With MerControl (steering wheel says QuickSilver) It is 120hp think Chevy Motor but Says MerCruiser on the valve cover (4 cyl). In Forward seems to limited 2-2500rpm's even when the throttle is all the way forward. When in reverse it Goes 5000rpm's is it possible that there is a rev limiter on these? I hope this is all the info one would need. New to working on Boats Might be a dumb question but thanks in advance for any help.!!