Re: my first boat
Recently sold my I/O and went back to a four stroke outboard. Gas I/O's have some benefits such as lower sound levels, however, some things to consider are these:
1) does the unit have a fresh water cooling system? If not the raw water from lake, ocean or ?? is ran through the engine, manifolds, risers, etc. and corrosion can be a big issue. If it is fresh water cooled, you then have two cooling systems to deal with, one is the raw water pickup that cools the second fresh water system in a type of radiator then the raw water is flushed back out through the manifolds and risers.
2) engine to outdrive parts such as the gimbal bearing, u-joints, housings, etc are not inexpensive to replace, and you will be replacing.
3) gas I/O's tend to wear out quicker (I'm sure that statement will cause an uproar) but here's my take- you have an engine generally produced for passenger vehicle use, someone says "hey lets upgrade a few of the internals and slap it in a boat" then it's run at 3200-4500 rpm's in a harsh environment such as salt water.
My last boat was a 1988 Bayliner Trophy with rebuilt 5.0 Chevy Engine (first engine only lasted roughly 350 hours). I put about 700 hours on the rebuilt engine and boat. In the six years I owned her I replaced the 60 gallon fuel tank, two sets of risers, one set of manifolds, one starter, one outdrive lower, and later the upper, u-joints every year, gimbal bearing twice, rebuilt carb once, etc. This is the very short list of what was done in that time. An older used boat with a gas I/O can be serious work and money.