tach for 1979 80 merc

fonthillhdtv · Aug 31, 2008

I need to add a tach to this motor can someone tell me if i'm on the right track with these parts i found on ebay. I think i need a 12 pole tach will this one work

achris · Aug 31, 2008

Re: tach for 1979 80 merc

What does the connector on the control box look like? That will determine if you have the right harness. If it have 3 flat female connectors, then it looks like you have the right harness... The tacho looks like one from an OMC engine (Johnson/Evinrude), and yes it should work.

Chris.......

fonthillhdtv · Sep 2, 2008

Re: tach for 1979 80 merc

I finally got the boat out on the water and it did not bog down on me. I think the problem was a restricted breather on the new gas tank. All i need now is the tach and I should be satisfied with this boat. The connector on the control has three pin's as in the picture below. You wouldn't happen to know what each pin out is for so i could just make up a cable and not have to bother ordering one

Chris1956 · Sep 2, 2008

Re: tach for 1979 80 merc

The two vertical slots are +12VDC and Ground. The horizontal slot is Tach sender. You will need a voltmeter to determine which is +12VDC.

fonthillhdtv · Sep 2, 2008

Re: tach for 1979 80 merc

one last picture I just found this one on ebay at a better price will it work

fonthillhdtv · Sep 3, 2008

Re: tach for 1979 80 merc

Achris do you have any advise for me on the last tach Picture I posted. The auction ends soon and the price is right, will it work for me?

achris · Sep 3, 2008

Re: tach for 1979 80 merc

It's got a selection for 12 pole alt, it should work....

fonthillhdtv · Sep 3, 2008

Re: tach for 1979 80 merc

thanks guys for all your help. I'm going to bid on it now. May have to tap your knowledge bank again if i have trouble hooking it up.
Thanks again
Frank

fonthillhdtv · Sep 17, 2008

Re: tach for 1979 80 merc

I finally got around to hooking the tach up, no problem everything seems to work.
now I need to know what numbers I should be looking for at idle and at wot any help would be great.
1979 merc 80hp on a 17ft sea nymph aluminum runabout

achris · Sep 17, 2008

Re: tach for 1979 80 merc

WOT for a 1979, 80 Merc... 5000-5500rpm
Idle, in forward gear, 550-650rpm

Chris...........

tach for 1979 80 merc

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Seaman Apprentice

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Seaman Apprentice

More fish than mountain goat