Hi I've a 2004 22' sport with a yamaha 115. recently the tach has been dropping off without a change in motor RPM. I could be running slow at 2500 RPM then the tack drops to 1500 with no warning of engine speed change. It never drops to zero but it often drops a few hundred or even more. any ideas? Loose wire, bad tack, bad connection
Tack erratic
- Thread starter supra1970
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Do you have a Yamaha factory tach or aftermarket? I would checking connections to start. I have replaced a number of aftermarket tachometers that do what yours is doing and the root cause was a faulty pole selector switch on the back of the tach that seems to lose connection and you get erractic movement of the tach reading.
I have had that happened twice. One time the plug-in on the back of the motor come out plugged it in that fixed it the second time I just bought a tack and stuck it in and that fixed it if you take it in and have them check it it’s gonna cost you a fortune you can buy a tack on Amazon, pretty cheap pretty cheap and stick it on see what happens
PartyBarge
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I have seen what you observe any number of times on our original factory tach. The solution has always been corrosion on the connections or the mode selector on the back of the unit. We live in a humid/damp climate nearly year-round and I have had the same problem with multiple boats.
For us, the fix has been to actually move the selector/connections. I have used some contact cleaner, but that stuff can kill some types of plastic...use caution. Frequently, just loosen and retighten the connections plus moving the mode selector and putting it back to the same position works. However, a better connector fix is to disassemble/clean/reassemble.