All of the engines vibrated at mid-throttle settings, a symptom of their single cylinders. From left to right, the Suzuki, Mercury, and Yamaha.

In March of this year, Practical Sailor covered small four-stroke engines in a market scan of the 4- to 9.9-horsepower range. This roundup featured 30 different engines and was loaded with data and specifications obtained from dealers and manufacturers. Many of the engines were inspected in dealer showrooms, but we did no field testing.

Since then, we've had a chance to hit the water with some of these engines. Two of our editors spent a full day with the three 4-hp four-strokes shown at right. They were lifted, mounted and removed, carried, started, run, checked for features, and examined under the hoods. Basically, we got to know them well.…