1969 Johnson 9.5 - Lacking Power

Hello - I purchased a 14ft aluminum boat on Monday with a 1969 Johnson 9.5
I'm new to boating; launched a boat for the first time today and learning a lot as I go. I know a good deal about older cars / motors and am mechanically inclined. The PO had the boat for 2 years and said the motor was serviced when he bought it and it wasn't in the water last year. I put in fresh gas and tested it out today. The motor seemed to run smooth, no surging, I had it WOT for quite a while, periods of 10 - 15 minutes and it held steady, just really slow, I'd guess 6mph, just a little faster than my trolling motor. I thought maybe that was it, but after watching videos on Youtube, guys get this thing hauling. I played with the R/L adjustment knob, and it ran best with the screw all the way in, full lean. When idling, the RPM would pick up all the way until the screw bottomed out and it seemed to run best this way at WOT as well. I cruised around for 2 hours and went through about a gallon and half of gas.

I did a compression test tonight, both cylinders are right at 60 after 4 pulls, I'm in Colorado over a mile up and from what I've read about the 9.5's, this is fine.
Both plugs are getting a spark
Spark plugs are J4J and gap was right on at .030
When I pull each boot while motor running, it sputters greatly then picks back up with the boot back on
Prop seems to be original

I plan to get a tach and check out the RPM, should ideally be at 4500 WOT from what I've read.
I need to get a puller for the flywheel, I'll take that off and check the points gap.
While I'm doing those, what other advice do you guys have to unlock this great beast?
Thanks

Good information in post #1-----But the response from the idle mixture needle tells me you need to look at the fuel pump diaphragm.---Or the float valve in the carburetor.------The true test of ignition health uses a test device.----So does spark on both leads jump a gap of 1/4" or more , yes or no ?

Thanks so much for the quick response. I wasn't able to get back to it until this afternoon.

I bought an ignition spark tester and grabbed a puller at the store. Pulled off the flywheel and it was beautiful underneath, clearly it had been serviced two years ago as PO said and wasn't used much since. Everything looked new, no oil or dirt anywhere. Checked the gap on each side, first was spot on. Second was a little open, so I closed it down to .020. Put flywheel back on then tested the spark. Top plug easily gapped 1/4", bottom plug gapped 1/4" so I backed out the tester a couple more turns to 5/16 or so and it gapped first pull. It appears ignition system is healthy, so now I open the carburetor? Or should I try to seafoam it first and see if that helps?

Gregory B I have a 1972 9.5 the same motor. Did you ever figure out what the problem was my motor is doing the same thing. I ordered the parts to do a carb rebuild on it and a fuel pump rebuild. If you have any advice or things to check to get this motor to run like it is supposed to

Not yet, that last post was this afternoon. I'll probably do some work next week closer to the weekend.

Is the carb throttle butterfly opening ?

Will it run ok with the hood off?