The Flex-Hone® for Boat Engines

Fourth of July boating means more than just fuel, food, fireworks, and fun.  For boat owners across the United States (and around the world), engine performance can be the difference between a relaxing day on the water and a frustrating day at the marina.  As Bob Gritz of iboats.com learned, damaged pistons can cause a marine engine to misfire, lose power, and idly poorly.  Without enough crankcase pressure, a cylinder cannot push enough fuel through the ports to the combustion chamber.  

Cylinder Honing for Boat Engines
In Bob Gritz’s two-stroke 15-hp Johnson engine, “a rogue piece of carbon” passed through the crankcase and into the top cylinder, where overheating (probably from over-revving) caused the piston to expand. Although the piston skirt became glazed and blued, the cylinder walls were hardened and thus avoided serious scoring. “The cylinder walls looked pretty good,” Bob noted, but also added that “they should be honed and then measured”. The tool he chose wasn’t a rigid honing stone, but the Flex-Hone® from Brush Research Manufacturing (BRM).

Flexible Honing and Surface Finishing
Made with a stiff metal stem and flexible nylon filaments, BRM’s Flex-Hone® tool features abrasive globules that are ideal for surface finishing cylinder walls. By polishing the metal gently, the Flex-Hone® “freshens” cylinders prior to re-ringing, but is not a material-removal tool.  Available in numerous sizes, grits, and abrasive types, the Flex-Hone® is used for engine block honing, surface finishing, deburring, and cylinder deglazing. Self-centering and self-aligning to the bore, the tool mounts in an electric hand drill and is easy-to-use. 

More Marine Applications for the Flex-Hone®
By restoring the crosshatch pattern on a cylinder’s walls and imparting a plateau finish, the Flex-Hone® also ensures optimum lubrication. For boat owners such as the members of iboats.com, smaller-bore tools are used.  Marine service shops use larger-bore flexible hones to maintain the big-bore diesel engines that power tankers, freighters, and other large ocean-going vessels. In addition to ship engines, the Flex-Hone® is used to refurbish marine pumps and valves. This versatile, flexible honing tool can be used on marine hydraulic cylinders, too.