Re: 1974 Mercury 50HP Tachometer
Kiwi, you can in theory put on a regular tach on a manual start but I tried and failed, so now I use a nifty item called a tiny tach instead. I have a 55hp Suzuki manual start which had pure ac power when I bought it. To get DC I bought and installed a rectifier for a Suzuki electric start and now I get pretty consistent DC 12v power and charging (though no regulator) but it has burned out two tachs that (I think) were hooked up properly. My solution is an item called a tiny tach that Norman158 on this site recommended. It's a digital tach that works on any 2 cycle motor. You just wrap its receiver wire right around the plug lead wires. You can search on "Tiny Tach" on google.com and see several positive reviews. For a boat application you will want to order it from the manufacturer, Design Technologies, because you will need a custom cable length -- the standard cable fitting is only 6 feet. Mine cost US$43 including shipping with a 15' cable. It works dandy and it's also an hour meter to boot.<br /><br />I'm guessing you could get a merc 50 rectifier to work from the same year electric 50 but maybe a merc guy can say if the stator/flywheel is the same?. Despite my experience, it ought to run a tach and you'd get 12 volts too. One comment if you go the rectifier route, once you install a rectifier you have to have a battery hooked up or the rectifier can be damaged. Trouble is with a manual start there is little draw and so a real risk of overcharging if you run a lot... <br />good luck
