Adjustment Of The Link Length Prior To Ignition Timing

[Craig P]

Just recently purchased a ProV 150 service manual for a 1986 engine. One of the worst I've seen, full of mistakes and bad illustrations. Would like to ask someone for help on adjustment of the link length.
Step 1 disconnect the joint links (these links are defined as magneto control link at the top of the magneto control lever and the throttle cam control link).
NOTE: The nut on the full-retarded side should be 2.5 mm off from the end of the magneto control lever.
This is the tricky part under link length dimensions are the following:
A 16 = 0.5 mm (0.63 = 0.02 in)
B 18 = 0.5 mm (0.71 = 0.02 in)
C 62 mm (2.44 in)
D 42 mm (1.65 in)
C and D make sense but what are they trying to tell me with the A and B dimensions? If anyone can recommend a better service manual than the Yamaha publication, I'd appreciate it.

[boats.net]

I'm not where I can pull the service manual at the moment but I think is supposed to be 16mm plus(+) or minus(-) 0.5mm and 18mm plus or minus 0.5mm not equal to.

[Craig P]

Thanks for the quick reply. I agree, plus or minus is most probably what it's supposed to be.