British Seagull Outboard Crankshafts

British Seagull® Outboard Crankshaft sits inside the crankcase, attached to the piston connecting rod, converting reciprocating motion to rotational motion for drive.

How does a British Seagull Crankshaft work?

The British Seagull outboard engine crankshafts are rotated by the British Seagull Outboard Piston through the British Seagull Outboard Connecting Rod. The connecting rod attaches to both the piston gudgeon pin and the crankshaft; via the off-set crank throw. The crank throw acts as a weighted lever arm during the combustion cycle, pushed round by the piston, creating rotational motion. This rotational motion is transferred to the drive shaft, rotating the engine gearing; which is later transferred into propeller rotation.

The crankshaft is housed within the British Seagull Outboard Crankcase and sits in two bearings, the top main bearing and the bottom main bearing. These bearings help smooth out the operation and reduce engine vibration.

The top of the crankcase is attached to the crankshaft nut, or pulley nut, and locates with the flywheel with the British Seagull Outboard Flywheel Key. The initial starting rotation begins the crankshaft rotation in unison with the ignition power.

Which British Seagull Outboards is this suitable for?

• LS/1291 - This part is suitable for all Forty Series British Seagull outboard engines including the Forty Featherweight, Model 45, Forty Plus and Model 55
• S1291A - This part is suitable for all Century Series, Model 102 and QB Series British Seagull Outboards.