Analog TACH choices for F115TXR

[chaugs]

There seems to be 2 choices for an analog tack (black face). A 6Y7-83540-80-00 and 6y5-83540-20-00 look to be compatible with my 4 stroke. The 6y5 is twice the price but specifies 4-stroke in my rigging guide. Will the 6Y7-83540-80-00 work for a 4-stroke? What's the difference other than letter color (yellow vs white)?

[boats.net]

Yes either one will work on a four stroke(the 6Y7 would require an adapter relay to work on two stroke engines). The 6Y5 gauge is the original gauge for 4 strokes and not sure why but is more expensive.
Either one would require a 6Y5-83653-00-00 Trim/oil harness connected to engine and a 6Y5-83553-N0-00 gauge power harness connected to key switch.

[chaugs]

Thanks for reminding me about harnesses

The outboard rigging reference sheet for the F115 calls out a 68F-82553-xx-00 trim/oil harness, but later on in my guide under a tach wiring reference table it claims the 68F-82553-xx-00 or 6Y5-83653-xx-00 can be used with the 6Y7-83540-80-00 Tach.

Is one necessary, or a better quality? Again there is a quite a price difference.

Thanks for your help. My cart is almost complete.

[boats.net]

You can use either harness on analog tachs. The 6Y5 harness is for 2005 and newer motors analog or digital gauges. The 68F harness is for 2004 and older motors and older tachs.