Crankshafts

The crankshaft converts the up-and-down motion of the pistons into the rotational motion that drives your propeller shaft. It is the most robust component of the engine, but not indestructible: if a main or connecting rod bearing seizes due to a lack of oil or low oil pressure, the crankshaft journals will score or become discolored from overheating. A machine shop can regrind slightly scored journals to an undersize, after which matching undersize bearings are installed. If the damage is too severe for this—deep grooves, cracks, or a bent shaft—a new crankshaft is the reliable solution.

In doubt? Have the crankshaft measured for wear, ovality, and runout before reassembling the engine. Overhauling an engine with a rejected crankshaft is wasted money: the new bearings will seize again within a few dozen operating hours.

In this category you will find new crankshafts for the Beta Marine Beta 30 and Beta 38 / Beta 45T and the corresponding Nanni N3.30 and N4.38; the range is continually expanding. Are you looking for a crankshaft for another engine from our lineup? Please contact us with your engine code.

Always install a new crankshaft with new main and connecting rod bearings, new crankshaft oil seals, and new connecting rod bolts.