Outboard engines are not like cars. Since the Force uses oil mixed at a 50-1 ratio fuel to oil, there are no scheduled oil changes. Change the lower unit gear oil at the end of each season--or if a problem develops--and change the water pump impeller say every two years --or sooner-- if it starts to fail as indicated by the engine overheating at high throttle settings and cooling down at lower throttle settings. Every couple of years --or sooner if it needs it-- replace the fuel pump diaphragm. Use fogging oil at the end of the season to prevent rust during storage. Change sparkplugs when they need it. Keep the prop in good condition to maximize performance and fuel economy. That's about it
12 hours is like nothing on an outboard. Especially a '97. That would be like a brand new engine. Can you trust the hour meter and seller? If so, enjoy your excellent buy.
Congrat's on your find.
Th information above is good.
I would do this:
1. Buy a manual.
2. Buy a manual.
3. Change the lower unit lube. Remember to change the fill/drain plug seals.
4. Change the water pump impeller. Sitting makes them take a "set" and they lose efficiency.
5. Run Sea Foam (NAPA) through the fuel system, on a regular basis.
6. Use a good quality TCW-3 rated outboard oil, mixed at 50:1 (one pint to six gallons).
I will warn you now. Having the engine sit for that long could have gummed up your carburetors. They may be OK but if the engine does not run smooth or lacks power, shut it down immediately and service the carbs. Remember, the oil and fuel are needed to lubricate the engine. If a carb is stopped up, that cylinder gets NO lube.
If it were me, I'd rebiuld them anyway. Cheap insurance.
Because the motor is a two stroke and uses an oil mix in the fuel to lubricate the crank, rods and sides of the cylinders, during combustion some of the oil gets burned and forms deposits that stick to the tops of the pistons and thru out the entire exhaust system. Especially the exhaust ports. These deposits if gone unchecked have the potential to not only rob the engine of h.p., but can cause pistons rings to become stuck in the grooves of the pistons. This can prevent the rings as well as the pistons from being allowed to float freely within the cylinder. This can result in either the rings and/or the piston skirts to scrape along the walls of the cylinder. Not good. As this will cause damage to rings, pistons and cylinder walls. Formation of deposits on the tops of pistons can also cause pre-ignition conditions inside the combustion chamber. This condition can quickly ruin an engine within a matter of seconds in the form of burning a dime sized hole thru the offending piston top. This happens when deposits within the combustion chamber remain hot enough to ignite the fuel/air mixture as it enters the combustion chamber prior to spark from the ignition system. This results in poor performance and high combustion temps. It is the high temps that literally burns a hole in the tops of pistons.
Now... not to scare you away from your new toy. Getting rid of these deposits is called "decarbonizing" the engine. The factory recommends decarbonizing the motor every 50 to 100 hours of run time. This can be accomplished two ways. Either thru the use of an spray thru the carbs while engine is running and then letting the solution sit for a few hours. Or, via fuel additive. I think most here apt for the fuel additive approach. One product that is very common and can be used as either is SeaFoam. Which also can be used as a starting fluid as well as fuel stabilizer. Another product that works well as a decarbon spray and as a starting fluid is good ol' WD40. Whatever you do never use automotive starting fluids as they do not have a lubricating oil which is critical to the life of your 2 stroke.
As Frank mentioned. Keep them in good tune and rinse them if used in saltwater and your motor should give you years of service.