You should check-out the Tohotsu or Nissan motors
You really should check out the Tohotsu or Nissan motors before you buy a new motor for your C-22. We have had our C-22 for 28 years and used a Johnson 6 hp, 2 stroke motor to power it, which did a very reliable job. (We still have the motor and will keep it as a spare). But, it consumed fuel and oil very rapidly, and we had to carry a great amount of fuel, about 12 gallons, when we cruised or boat 35 miles or more from our slip, which we have done many times on the Chesapeake Bay.
Last summer, my son bought a Tohotsu outboard for his C-22, and his gas mileage was 3 times better than mine. It seems unbelievable, but it is true. This motor is also light weight at 57 lbs, which is the same as our old Johnson 2 stroke motor. This really makes for a weight savings because of how much less fuel we have to carry, not to mention not having to worry about running out of fuel, and not mixing oil with the fuel. I haven't felt good about mixing oil with the gas, knowing that that oil was going into the water that we were swimming in.
Anyhow, I bought one of the 6 hp long shaft Tohotsu motors for my C-22 this spring. I just used it on my boat for the first time yesterday. Like my son's motor, it ran just fine.
This motor is not perfect though. When we use our motors on our boats, we tighten the drag knob that prevents the motor from rotating side to side, so that the boat goes straight, unless we want to change the motor by taking the motor's tiller and rotating it side to side. This works out great for putting the boat into or out of a slip. It works like thrusters, and you can really maneuver your boat very well into very tight spots. The problem with the Tohotsu motor is that right in the middle of where you would normally position your motor for going straight ahead, there is a flat spot ground into the vertical shaft that reduces the drag. This is not good. I have notified Tohotsu of this last year with my son's motor, but I don't think that they understood, or wanted to understand, and my motor had the same design defect as his. He figured out how to modify his motor to overcome this problem, and last Friday I made the same modification to my motor. Both of our motors now steer perfectly. But, neither of us think that the average boat owner could make the modifications that we made. We both have considerable machine shop experience and are both mechanical engineers.
Another thing about the Tohotsu that I'm not crazy about is that there are two positions that the motor kicks-up to. The first position is a little low, so that the motor is still partially in the water on a starboard tack. In the upper position, the motor is almost horizontal, a little too high in my opinion. My son likes this. I may modify this for next year, or I'll get used to it this summer.
Despite what I wrote above, I do really like the Tohotsu motor. The light weight and extremely low fuel usage make it just what I want on my boat. It was priced well and we purchased both of our motors from Onlineoutboards.com, and they were delivered right to our house. I did get a propeller that they called an "elephant ear" propeller that has bigger blades and lower pitch than my sons. We still haven't compared them against each other. I'll be breaking my motor in for quite a while at 3/4 throttle or less. My son just used his motor sailing in the Florida Keys. He sailed from Key Largo to Key West, then back to Key Largo then to Miami. I joined him in Miami and sailed back to Key Largo. When the cruise was over, we drained 6 gallons from his fuel tank into his Suburban for the drive home.
I must comment on the Honda motor that we used as a loaner on our boat several years ago. One of the members of a C-22 fleet that we were in lent her extra Honda 5 hp motor to us. It was heavy. It was very good on fuel consumption too, but had another bad characteristic that was not good. Sometimes when you would pull the starter cord, it would pull back and just about pull your arm right out of the socket! If you had one of these motors, you would probably figure out how to avoid this, or you would be sailing with only one arm, but I can tell you that our Tohotsu motors start almost effortlessly. Don't just buy a Honda because of the name Honda. We have Honda motorcycles and know that they can build wonderful machines, but never understood their boat motor engineering. We couldn't understand why this sailor used an old 2 stroke motor on her boat and not the Honda motor that she kept in her garage. Once we had the Honda motor on our boat we understood, and were happy to get our old motor back from the shop.
If you or anyone else is interested, I took photos of the modification that I made to the motor steering this past Friday night, that I could post. It was a little strange taking a brand new motor and modifying it, but I knew that it had to be done.
I have a long shaft motor on my C-22, and my son has the extra long shaft on his. The shaft length that you need depends on the motor bracket that you have and how high it is located on the stern of your boat.
I also don't recommend a 4 hp on a C-22. They can't push the boat at hull speed when you might need it most, like when a storm is coming. That's why my son bought the new motor for his boat in the first place. He has a 4 hp motor in my shed that is just fine, but not adequate for where we sail. I know that you said that you were just sailing on a lake, but why underpower your boat on purpose. Also, a 8 hp's extra weight is no advantage in my opinion.
I hope that this helps, and feel free to reply with questions. Aldo