Low RPM on take-off

Also my mechanical tachometer is off by -200 rpm. I have a digital tru tach that we used to confirm.

Does your engine/prop combo make static RPM?

Got a few more hours now. My original numbers are certainly not accurate. Climb speed at 80 mph indicated and 2000/2050 rpm, maybe 2100 at the most. Cruise rpm 2100 or 2200. IAS 115 or so. Solo under gross wt. At level cruise and full power I have never seen RPM above 2300. Need to do some more checking. Those are the numbers I recall. Need to write down next time I fly. Too much fun looking outside! Thanks for the feedback.

Having flown Bonanzas for the last 23 years, just getting used to a fixed pitch prop again! Slow learner!

I would think that climb RPM is about right. Maybe a little low.
Your ASI may be off, though. A C85 with 7148 prop is unlikely to indicate 115 to 120mph at 2350rpm.
You might have both your tach and ASI calibrated.

Or maybe I misread that. Are you saying you’re getting 115-120 at 2350, which is your full power? Or is your full power a different value? Typically 2575 for a C85.
Even at redline, 115-120 would be exceptional for most C85s.
I consistently get 118 at 2575 but I have a C85 Stroker, which gives me 93 or so HP. 7148 prop.

New Ercoupe owner here. Just finished my second hour in the plane with instructor: Four take-offs same number landings! On each take-off full power standard temp sea level, Gross Wt or slightly above, RPM on climb never got above 2100-2150 climbing at 80mph. Cruise RPM came up to 2300 -2350 with full power indicating 115-120 mph. Engine C-85 with McCalley prop IA90 CF71-48. My concern: shouldn't I be getting more RPM on climb out? Thanks in advance for your help.