Adding a tach to an old outboard

[onthewater102]

I have what was a 20hp 2-stroke pull start tiller motor that is now converted to a remote throttle/shift setup but still requires a pull start and has no electric start components. I have an induction tach but the wire is not long enough to reach my side console and I'd really like to add a gauge so I can see what's going on with the motor without having to turn around.

My question is can I pick up a signal for a tach from one of the connections available to me?

Here is my motor's wiring diagram, note this motor does not have the electric start components (stator, rectifier, starter, solenoid & e-choke).

 

[DaleH]

Many extend the length of the wiring run on those induction tachs, I'd just up-wire the size a bit ...

 

[Dustinmikl]

The brown/white or brown/ yellow should work just be sure to check voltage on the wire with the motor running to make sure it is compatible with your tach trigger signal

Sent from my SM-N930P using Tapatalk

 

[onthewater102]

I was looking at the Sierra Amega https://www.amazon.com/Sierra-58255P-4-Strokes-Amega-Tachometer/dp/B000C4O0KK/ref=sr_1_21?ie=UTF8&qid=1472673899&sr=8-21&keywords=outboard+tachometer and I actually got through to customer service when I called.

I wasn't overly comfortable with the technical knowledge of the CSR - they didn't understand what I was referring to when I mentioned a stator and I'm not sure they knew the difference between a 2 stroke and a 4 stroke (or cylinder for that matter) so I don't have much confidence in them telling me that it should work other than it sounded like they were looking at the installation instructions. They did refer me to the manufacturer's tech support which was much better. (941) 538-7775 for anyone that wants to skip the useless conversation I had to go through.

Tech support indicated it needs to be on the AC side of the rectifier, connected to the stator side assuming it has the sufficient number of magnetic poles (min 4 max 12) and will work based on the pulses determined by the number of poles on the stator divided by two. Those would be the black-white and black-yellow wires in the diagram.

 

[onthewater102]

Looks like I've only got a two pole stator in my setup so this isn't going to work. The electric start accessory stator only has 3 poles so neither looks like they would work.

Induction tachs look like they use a coaxial cable...that's got to be tricky to extend.

Looks like my only option would be ordering a tinytach & having them extend the cable @ the factory...works out to the same price as the other would have been - just not as clean looking in the dash. Also sux that you can't replace the battery so needs to be replaced every so often for the full price.