Merc 110 9.8 High Speed Jet on Carburetor

[Sandcassle]

Merc 110 9.8 HP S/N 3006929 1971

Hey, all?

I feel my engine is making about 90% power at Wide Open Throttle.

I?ve disassembled and cleaned the carburetor. It really didn?t need it.

I installed new spark plugs and plug wires.

I?m using brand new fresh gas.

I also noticed the butterfly valve on the carburetor wasn?t fully open when the throttle twist grip was twisted for max throttle.
I installed a piece of thin walled rubber hose on the cam slider pin to take up the slack and that worked well. The butterfly valve now reaches full Wide Open Throttle.

So, off to the lake we go?

My boat is a 10? 6? Zodiac 310 Inflatable.

With 2 adults on board, I am able to get on plane and obtain a max speed of 17.1 mph. That?s pretty darn good for 9.8 HP.
However, if the water is choppy, it?s difficult to get on plane. My ears tell me the little motor is just not quite making its maximum rated power.

And here?s another reason I?m saying this:

As we?re cruising along on plane at Wide Open Throttle, I can hear a slight increase in RPM if I very lightly back off on the throttle. But if I twist the throttle back to full throttle, I can hear a slight drop in RPM.

So, I?m wondering if the engine is running a little rich when at Wide Open Throttle. I feel like if the carburetor had a high speed adjustment screw, which it doesn?t; this is all that?s needed to get that max RPM.

Is it possible this motor is running too rich at Wide Open Throttle?
Are replacement high speed jets available to correct this problem?

Any help would be greatly appreciated!

Roy