A Spring Starter uses potential energy stored in a spring wound up with a crank to start an engine without a battery or alternator. Turning the crank moves the pinion into mesh with the engine’s ring gear, then winds up the spring. Pulling the release lever then applies the spring tension to the pinion, turning the ring gear to start the engine. The pinion automatically disengages from the flywheel after operation. Provision is also made to allow the engine to be slowly turned over by hand for engine maintenance. This is achieved by operating the trip lever just after the pinion has engaged with the flywheel. Subsequent turning of the winding handle during this operation will not load the starter. Spring starters can be found in engine-generators, hydraulic power packs, and on lifeboat engines, with the most common application being backup starting system on seagoing vessels.
Some modern gasoline engines with twelve or more cylinders always have at least one or more pistons at the beginning of its power stroke and are able to start by injecting fuel into that cylinder and igniting it. If the engine is stopped at correct position, the procedure can be applied to engines with fewer cylinders. It is one way of starting an engine of a car with stop-start system.