Speed RPM and oil leak AQ130c 17ft Glastron Bayflyte

"I'm new to this board, bu

"I'm new to this board, but find it very helpful.
I have a 1976 Glastron Bayflyte with an AQ130c.
Does anyone have any idea why I can't get more than 4000 rpm wot, rev's out of gear no problem.
Is it just the prop ratio ? Timing, carbs, etc are fine. The speed looks about 28 mph. Just curious.
One more question.
I show 163-170 psi on compression check, book says 187-200, I seem to be blowing oil out of the oil pan, just tightened up the bolts one more time and will check on next run, I also have a small amount of smoke coming out of the air filter.
I have added some bars leak for now, but does anyone think the oil ring is worn, plugs look dry.
Thanks for your time.
Dave"

"Low compression will reduce t

"Low compression will reduce the engine power output, but if you cannot reach higher RPM you may also have a propeller too large for your application.

To find out for sure whether or not your problem is worn rings or leaky intake/exhaust valves, I suggest that you should perform a leakdown test in your engine."