2001 Edition Yamaha F225A and LF225A Outboards Service Manual, Page 15Get this manual
Features and benefits Tensioner timing chain tensioner is provided at the mid-span of the timing chain, between both camshaftsThe timing chain tensioner uses the force of spring to maintain its tensionAfter the engine is started, oil is pumped into the tensioner, and the resulting pressure causes the tension to increaseA total of three tensioners are used, one for the timing belt, and one for each timing chain of both banks, to maintain proper tension and to ensure the reliability of the valve train