Re: 1957 Johnson 18hp
It should do just fine with that boat & load. It's probably got a 9" or 10" prop on it already, which is what you would want. See if you can find any numbers on the propeller - you may have to remove the nose cone, drive pin and thrust washer to find them. You can make any engine suit any boat by changing propellers.<br /><br />For working on an 18hp, there aren't many "special tools" you need. You need something for pulling the flywheel to work on the ignition system. Many here (myself included) use automotive 'harmonic balancer pullers' because they're cheap and easily found. You need torque wrenches (inch-lb and ft-lb) for torquing flywheel nuts, head bolts, that sort of thing. There's a couple other specific tools for specific situations, but they're all easily found, fabricated, or worked around.<br /><br />Parts abound. Much is still available from the dealer for very reasonable prices. Almost as much is available aftermarket. Iboats sells a number of these aftermarket parts, as well as NAPA autoparts, and 1000 other web based stores. Parts that are very expensive or not available (say, the flywheel or some bracket or another) can easily be purchased from a junkyard, online or otherwise, or even ebay. The 18hp was sold for many years and it was very popular.<br /><br />Manuals can be purchased from maxrules.com, kencook.com, theoutboardwizard.bizhosting.com, or marineengine.com. There's a couple aftermarket manuals but they aren't nearly as good as the factory ones. If you want to save some money (that manual is very thick & expensive) you can get a CD from acmeoutboards.com.