First check compression. Should be 110+ and even across both cylinders. If compression is good, other items can be fairly easily addressed. The nice thing about these motors is you can work on them with mostly basic tools. You will need a harmonic balance puller to remove the flywheel, but you may be able to borrow one from an auto parts store. Under the flywheel are the points, condensers and coils. Coils and condensers will most likely need replacing, points usually can be cleaned up and re-set to .020". While under there, I would also replace the plug wires. Once the ignition is gone over, you should get a nice snappy spark jumping 1/4"+ gap. A spark tester can be had for about $10 from an auto parts store. Then on to the carb which will need a cleaning/rebuild. Carb kits are readily available. I ususally change the gas lines when I rebuild the carb. The motor will also need a new water pump impeller (about $15). It sits on top of the gearcase, which has to be removed from the motor to get to it. The gearcase should be drained and the oil changed. If there are any signs of water in the gearcase, it will have to be re-sealed. You can find specific instructions for all these procedures on this forum, or pick up a service manual for the motor. Don't be afraid to ask questions here. There are many knowledgeable people willing to help.
