OFF-SEASON STORAGE TIPS
WHAT YOU NEED TO KNOW FOR STORAGE

Proper preparation for periods of extended storage of your outboard requires a comprehensive look at the entire boat/motor/trailer package. Of course, if you just have a small "kicker" that you use on a cartopper, the only thing you have to deal with is the motor itself!

Gather the following items, along with your boat, fuel tank filled, in an area where you can run the motor on your "flush" attachment.

Applicator containers of: storage "fogging" oil, fuel stabilizer like Sta-Bil or OMC 2+4, anti-corrosion spray, and a good spray lube product like LPS2 or OMC 6 in 1. A trailer jack. Your toolbox.

Proceed as follows. First, add some fuel stabilizer to the gas in the recommended amount. In fact, the best thing to do is add it before you fill up the tank! Why fill the tank? (After all, its gonna sit - right?) This will prevent a couple of unpleasant things from happening, like condensation.
And oxidation and subsequent spoilage.
I hope you can get undoped gas - oxygenated and gasohol fuels are a NO-NO! if you cannot get anything else, you must COMPLETELY drain ALL the fuel system. And I mean AAALLLL. The lines, the VRO on OMC motors, the whole monkey. This stuff's deadly.
Start the motor on the flush, run it up to warm and to ensure that the treated fuel gets in to the whole system. Apply the fogging oil to the carburetors equally - some Johnson and Evinrude motors have a fitting you can apply this thru via the special products sold by dealers; most you will have to look around for openings to shoot the stuff through, maybe even remove the silencer cover. You'll get lotsa' smoke. Great. So disconnect the line and run the motor out of gas at IDLE. Keep fogging. Note: OMC motors with VRO system you will have to shut it off and drain the carbs manually or depend on the stabilizer. If you try to run the gas out, the VRO will fill the carbs with oil, this will turn to goo by spring.
After the motor is run, unhook the flusher, drain the gear case, and refill with fresh lube. If there is water in the old stuff, it could freeze and burst the case.
Pull the spark plugs, tilt up and spray more storage fogging oil in the cylinders directly, then turn it by hand to distribute it on the cylinder walls.

My late 50's 19' MFG restoration, fresh Imron. Awesome!

This should take care of the motor innards. But - wait - there's more! You're not done yet...
Here's the good stuff. Clean the powerhead up to remove accumulated crud and any salt deposits. Let it dry, douche it good with "6 in 1" or equivalent, and coat electrical connections with anti-corrosion spray.

Next, (unless you have hydraulic steering) disconnect the steering link arm from the motor and unscrew the big nut on the motor tilt tube. remove the steering cable from the motor and extend the cable all the way out. Run an oily rag down the tube to remove all the crud from the bore. Clean all the gunk off the cable and let it hang down for awhile to get any water out. then spray it and inside the tube with the anti-corrosion spray. Leave it off and extended, hang it up under the well where it won't get in the weather. For hydraulic, remove the extenders that hold the cylinder and remove the rod thru the tube, clean as above. You ain't seen grief til this stuff all seizes up and you get the bill.

When you have the boat where you are going to store it, disconnect the battery and REMOVE IT from the boat; put it inside on a board and keep a trickle charger on it a couple days a month. Clean the terminals with baking soda and spray with the anti-corrosion treatment. Spray the area around the base of the powerhead and the trim (if equipped) with anti - corrosion.
If the inside of your motor cover has a foam sound blanket and you use the motor in saltwater, see if it is a closed cell foam; if not RIP IT OUT! Salt is hygroscopic; that is, it attracts moisture and the two do a great job of eating up the motor. All OMC motors use cheap foam. 86 it quick!
Store the motor tilted DOWN to running position. And when you put the cover back on, don't wrap the motor in a piece of plastic or a "Blue" tarp. Cover it up with a cloth cover and set a piece of plywood or something on top to keep rain off. Otherwise condensation will never dry off the block. Same goes for the boat. It's gotta breathe. If you have a really fancy rig to store outside, have a pro come out and shrink wrap the BOAT. Not the motor.

Last, but not least, attend to the trailer. Jack it up and pull the wheels and hubs. Repack the bearings; if you have Bearing Buddies, ensure they are full. Put the thing on blocks and store the tires in the shed. Spray anti - corrosion on any unprotected iron.

SO, there you have it. With any luck, on that first nice spring day, your steering will steer, the trailer will roll, the motor will mote and a good time will be had by all. You may even save enough to upgrade that old PC you are reading this on!
One last caveat! Check the registrations on the rig & trailer and renew them early so next spring you won't get fuzzed. I remember the fine spring day I went to the lake Sammammish launch ramp near Seattle. About 125 rigs parked there, half with expired tabs, and Smokey just writin' up a storm!