Tachometer install

[gregsails]

Trying to add a new tach. The instructions say to hook one of the wires to the "W" on the alternator. I have an old school original 35 amp alternator but see nothing that says W. Anyone have any idea?
Thanks
Greg sail 696

[Dave Neptune]

You have a "diesel" type tach not designed for a gas engine. That tach needs the sensor in a diesel style alternator to sense RPM's and would also need calibration.

A gas engine style tach uses the ignition spark for sensing RPM's.

Dave Neptune

[gregsails]

Ahhhh, well that's not good. Glad I didn't spend to much money. Thanks Dave.
Greg

[gregsails]

Don't really need a tach. Just want one. Someone, not sure who on this site steered me to a inexpensive one that unfortunately got destroyed by the boom at the end of the season some years ago.
Anyone know of any that work for gas that are not crazy expensive. I'm in Canada. By the time I would get the Moyer one, it would cost me over 250.00. I don't want one that bad
THANKS
GREG Sail 694

[GregH]

Don't really need a tach. Just want one. Someone, not sure who on this site steered me to a inexpensive one that unfortunately got destroyed by the boom at the end of the season some years ago.
Anyone know of any that work for gas that are not crazy expensive. I'm in Canada. By the time I would get the Moyer one, it would cost me over 250.00. I don't want one that bad
THANKS
GREG Sail 694

You could go with Farias-Beede or Seastar or Sierra brands.

https://www.marineoutfitters.ca/images/products/Faria%2033832.jpg

[Dave Neptune]

Check in parts houses, Amazon if you have it in Canada or most any marine store. A cheap jippo one will work just fine. Also check the classifieds in your area. An automotive one will work fine for quite a few years in a marine environment. I used one on my boat mounted inside and it lasted 34 years for me and I'm sure the current owner is still using it. I did mount it in the cabin where I could see it from the cockpit. It was a mid range quality one from Stewart Warner. And it was a few years old when I mounted it.

When doing tuning I would sometimes switch it to 8 cyl for additional sensitivity.

Dave Neptune

[sastanley]

greg, I just had the VDO tach fail on my port engine. I got one like Dave describes on eBay for about $30 with an hour meter and multiple color LED backlight. It is not as sensitive, nor is the sweep as smooth as an analog tach, but after calibration (already had a handheld tach for fine tuning the A4) it does seem at least to read the correct RPM, so I am not tuning/syncing by ear.

It will do until I totally re-design the 1980's dashboard on my power boat.

[joe_db]

All may not be lost. My tach had settings for gas or diesel, either way it counts pulses or cycles.
Hook it up and see if you get any reading. The wire that would go to the alternator goes to the coil negative. If it works at all, you may be able to calibrate it to the correct reading.

[joe_db]

FYI

https://www.moyermarineforum.com/forums/showthread.php?t=11410&highlight=tachometer