Flo scan makes one as do most mfg's. Flo scan is pretty universal. The are not cheap though. The 2 stroke engines get the best fuel economy between 3700 and 4200. On 4 strokes, they get good around 4300 to 5000. Just a rough guide... all depends on the setup. Anyway, thesystems areexpensive, but I like them. They also can give a warning of a fuel or running problem when the usage starts getting higher than normal.