Tach

TunaFish389

Petty Officer 2nd Class
Joined
Apr 26, 2018
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184
Took boat out today and turning key to on position tach was maxed out, engine not running. Started and warmed up and still maxed out. About two minutes underway tach started working properly and stayed that way for remaining of trip. Any ideas where to start looking for the cause.

1984 Ekbo 16.5' mercruiser 3.0 alpha one gen I drive. Thanks.
 

alldodge

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40,582
Check the + and - on the gauge. If they are good, might be a failing gauge
 

Bondo

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Ayuh,..... Boat tachs live in a rather hostile environment through most of their lives, which are relatively short, compared to a car's tach,.....
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Ayuh,..... a rather hostile environment .....

Is that like people who prefer proven modern, superior technology over antiquated century-old relics trying to help in forums full of ancient people attached to the past? :lol::lol::lol: (looking at you Scott Danforth ;):D)

Yes, if the wires and connections to the tacho are all in good condition, then the tacho is dying. Possible it's quite moist inside and with the time running dries out enough to start functioning again... If you'd like to test out that theory, then remove the tacho, put it in a very low oven (about 60C) for a few hours and see if it works immediately after that...

Chris.............
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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achris , the tach in a boat is less than $5 worth of components ($1 air core, $1 stainless bezel, $1 glass with anti fog, $1 plastic and metal and decal, and $1 labor).... Its a wonder they last more than the 1 year warranty period
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
achris , the tach in a boat is less than $5 worth of components ($1 air core, $1 stainless bezel, $1 glass with anti fog, $1 plastic and metal and decal, and $1 labor).... Its a wonder they last more than the 1 year warranty period

The state of the world these days. People keep shopping on price, and this is where we end up... :facepalm:

Chris......
 

TunaFish389

Petty Officer 2nd Class
Joined
Apr 26, 2018
Messages
184
I will clean up contacts and go from there.. There is a singal wire going to the coil? It been awhile but think that is where my tester hooks up to. Thanks again.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,304
the grey signal wire is connected to the negative side of the coil (the one pulsed for the ignition)
 
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