Force 50hp tach - won't work

[Tuni]

I have a Force 50hp 2stroke (1992) and a new set of gauges. The tach appeared to be wired correctly by a boat shop, but it doesn't work. I removed the Faria tach to hold it closer to the motor figuring everything would be direct to the gauge and there wouldn't be any shorts. I wired positive, ground and then the grey wire from the rectifier. The pulse for Faria was set to '5'. Nothing happened. I switched to all the different choices of pulse settings and none of them gave a reaction. Can I try the purple wire (hanging by itself)?

 

[Silvertip]

Only if you know what that purple wire carries!!!

 

[Tuni]

No I don't know. I thought I read a post where someone used a purple wire and the tach worked. I'm just at lost trying to find a way to make sure the tach needle does something to determine if the tach is defective. It's too late to go back to boat repair shop. My wire diagram doesn't even have a purple wire hookup. The boat repair put a 3 cylinder stator on my 2 cylinder....but it works fine (I think).