Tachometer hook up on 1965 100hp Merc

[Caddy_Kid]

I would like to hook up a Faria tachometer to my 1965 (no serial number plate, but was ID'd by you folks earlier) 100hp Mercury. It has the double coil ignition system, and no plug on the throttle control box.<br /><br />It would seem that I could simply attach the tachometer to one of the coils, but is it really that simple? Also, which pole setting should I use? The instructions that I found online only went back to 1970. Thanks.

 

[Clams Canino]

Re: Tachometer hook up on 1965 100hp Merc

All modern tachs are stator signaled.<br /><br />Hook the tach to one leg of the stator where it meets the rectifier. Then set the tach for a 12 pole stator. Done.<br /><br />-W

 

[Caddy_Kid]

Re: Tachometer hook up on 1965 100hp Merc

So basically either of these two leads? Does it matter which one? Thanks.

 

[Clams Canino]

Re: Tachometer hook up on 1965 100hp Merc

Nope either one is the same. <br /><br />I assume you know if the rectifier is good (if it's not the battery won;t charge).<br /><br />-W

 

[Caddy_Kid]

Re: Tachometer hook up on 1965 100hp Merc

Truthfully, I dont. This is a "new" boat to me. All I know is that the previous owner demonstrated that the motor ran, then I took it home in November. Been too cold to try to start it. However I am planing on trying it out within the next week. I will hook up a multimeter to the battery and see what its putting out before and during the run. I wont be connecting any instruments to it before I verify that it is charging. Thanks!

 

[Clams Canino]

Re: Tachometer hook up on 1965 100hp Merc

OK... if you get no tach signal off either or both of the stator poles, odds are the recifier is blown.<br /><br />Also... that charging system is unregulated, when the battery hits full charge, the system voltage can rise pretty high. At around 16v the condensers in the ignition leak, and it stops running till it cools down and the bat voltage drops. I had a '62 1000 and it took me a while to figgure out what was going on.<br /><br />Best to have a voltmeter on the boat and run the lights 24/7 if you find it overcharging.<br /><br />Lastly if you wind up playing with the points, be carefull. You set each one set for 90 degrees of dwell and the second set to open exactly 60 degrees after the 1st set opens - regardless of dwell on the second set.<br /><br />=W<br /><br /><br />-W

 

[Caddy_Kid]

Re: Tachometer hook up on 1965 100hp Merc

I just got done running the motor and everything works well. It does charge according to my multi meter. In addition to the tach I will have a head temp sensor and a volt meter. Tach I will have just because there is a hole for it in the dash. Probably the least useful one there, but at least it looks cool.<br /><br />I have heard that because the motor will at some point be charging the battery to over 12 volts, that gauges such as a temp gauge can read high when it is really normal.<br /><br />Had to unplug the tell-tale water hose. There was something that got jammed in there. Works fine now.<br /><br />I do have some water coming out around #2 plug. I beleive that I have read to try either epoxy or a high temp silicone before trying to remove the water jacket plate, as bolts can break.<br /><br />Sure ran smooth though!

 

[Clams Canino]

Re: Tachometer hook up on 1965 100hp Merc

Tach is very important. Prop the motor to make 5000 to 5300 at WOT and cruise it at 4200 for day to day use. <br /><br />Yes... try to patch the leak from the outside. DRY it real good... and them hi-temp silicone a spark plug washer in there (that's drilled out a bit so you can use a washerless plug in that hole easily). Let that all dry a few days too.<br /><br />-W

 

[Caddy_Kid]

Re: Tachometer hook up on 1965 100hp Merc

Sounds like a plan! Thank you sir.