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Mercury 115 Tachometer

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rltf

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" I bought a used boat with a

" I bought a used boat with a 1986 Mercury 115 on it. When the motor idles it reads 2000 rpms. At full throttle it pegs the tachometer at 8000 rpms. The tachometer is a three wire and on the back there is a setting with 1, 2 3 & 4. The arrow is pointed at 1. Is the tachometer bad or does it need to be adjusted? Does anyone have any suggestions? Thanks "
 
Hi. Try changing the setting

Hi. Try changing the setting until idle rpm is correctly displayed. If I remember right it should be pointing to #4.
 
I believe the 1 2 3 4 is the

I believe the 1 2 3 4 is the number of cylinders the motor has. That is the way an automotive tach is. I would try that and see what it does. Just set the 1 2 3 4 to the number of cylinders.
 
My 115 is a inline 6. I will

My 115 is a inline 6. I will try the other three settings and see what happens.
 
"Check the URL below. It woul

"Check the URL below. It would appear from the chart that James is correct that #4 or 4P is the correct setting.

Given that you only have 1-2-3-4 as settings, I suspect you may have the wrong tack.

http://www.tflx.com/PDF/99320.pdf"
 
" I hope I'm right.. if no

" I hope I'm right.. if not I've been running my 86 merc L6 (115) at the wrong RPM for a while, but as far as I know it's supposed to be on 6P on those. "
 
Went fishing on saturday and

Went fishing on saturday and tried different settings. I think it's right now. Thanks to all.
 
" Jon,

I went back to the c

" Jon,

I went back to the chart and re-read it and you are correct. It should be 6P. I read the 2 cylinder line instead of the 2 stroke line.

Anyhow, it's good that Rltf got his sorted. "
 
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