Yamaha F100B F100C Outboards Factory Service Manual, Page 11Get this manual
IdentificationFeatures and benefits Features and benefits Power unit
The F100B and F100C have been developed on the bases of the F100A, which has been recognized as being environmentally friendly, with established emission control, and which has received high marks as an efficiently superior model with high fuel economyBlowby gas, which is discharged from the engine, is returned to the intake silencer and reburned to purify the exhaust gasThe intake passage and exhaust passage have been arranged around the engine to make the entire engine compactWhen compared to small, 2-stroke, V4 engine it is compact like an in-line, three cylinder engine::