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dynafoil
12-30-2004, 06:57 PM
I'd like to know if a tach I found laying around my shop will work on my '92 Mercury 25 twin. On the backside of the tach there are settings for various cyl/pulse combos. There isn't a setting for 2 cylinders, only 4, 6 and 8 cylinders and for 5 and 6 pulses. Will the position for 2P 4C work or am I outa luck?
Thanks alot for the help.

mercmatt22
01-20-2005, 09:44 PM
best bet is to hook it up to a known good tack (timing light ext.) and play w/the tack till it reads right. I have done this on new boat riggs where you cant see the setttings on the back of the tach. u can just feel them.

sho305
01-29-2005, 10:34 PM
The cyl settings are for auto engines, the pulse might work. Go to a site like Teleflex and they list all the OB motors and what pulse they take for their alternators so you can set it right. Most boat tachs are the same, most motors are a couple types except chrysler the odd balls. If you don't have a charging system on an old or small outboard you might not be able to use it but you can try it anyway. You can use a tiny tach on most small motors though, they don't cost too much.