I recently purchased a 99 SX186 w/ a 130 Yamaha. It was not running when I bought it. I had to rebuild the top end, so I have no idea what the tach should read.

I did a thorough search and have read a dozen or so posts, but nothing with a similar problem for this application. It seems like the tach is reading high. At idle it reads 1200-1400 and max RPM is past 7k. The switch on the back of the tach was set on #5 out of 1,2,4,5,6. Its says next to the switch "set to ALT".

The prop is a 12 5/8X21 and the top speed is 47mph GPS. I think it should be running about 5500rpm at that speed. The outboard is mounted in the third hole from the top.

Does anyone know what the proper setting is for this application or who the manufacturer of the tach is?