new yamaha tach question

[skipjack]

Just got a Yamaha tach for my 98-C40. Between 0 and 1K there is only one line for rpm. After 1K the face has a line for every 200. Can anyone tell me how many rpm this single line represents or is just guess work up to 1K. I would figure something a little better from Yamaha for $150. Thanks

[boats.net]

The one line would be 500 rpm's.