Very good time to remind folks that those little dirt bugs (mud bugs, dirt dobbers, mud wasps, whatever you call them) and their nests can wreak havoc on outboards. In fact, of the 2 or 3 powerheads I've had to replace or rebuild, all of them were preventable. Whaddya mean?
Those bugs build their nest as the rig is sitting, and out here boats tend to sit a LOT. Years in some cases. Then it's the night before the big trip, dig it out from underneath all of the junk stacked on top of it, fire the motor up, and it runs. Great. Shut it down and continue your readiness preparations.
BUT...the discussion here is dirt dobbers. Those cute little dirt nests. They build a nest on the side of a motor, under a cowling, in an air intake, bolt hole, flywheel, stator, wherever they think is a good spot. Then you go use the boat/motor. As you're running, those nests (which are DIRT) begin to come apart due to the vibrations among other things. There IS some air flowing under there with the engine running, and that air flowing is what does the work here. That dirt that has gotten broken loose or has been flung or ground off of the flywheel gets into the engine. Why? Outboards typically don't have air filters. They dont' need them. There's not much dirt out on the waterways. All that dirt goes right into the engine where it turns to basically sandpaper. Scores cylinder walls, eats up crank & rod bearings, etc. Basically destroys the engine, and it doesn't happen immediately-it can take years after the dirt entry for it to finally show it's effects.
I suggest pulling the cowling before starting the engine. Just pull it anyway once in a while to inspect everything, and look for the evidence of rodents and dirt dobbers. If you see nests, clean them-and I use permatex Grez-off, which works absolutely wonderful-and safer than using compressed air-by far. I love that stuff for a lot of different things from degreasing to cleaning parts to outboard powerhead cleaning. No, cleaning the powerhead won't hurt it UNLESS there's other problems, but I do suggest being mindful in spraying the coils off AND plug or put a bag over the air intake to keep water out. Doing this and doing it carefully, you'll get all of the dirt off of the engine-and the engine itself will look nearly brand new. I make a practice to do it every time I service a customer's outboard, but that's just me looking out for other folks' investments.