Tachometer setting question

[TN444PSD]

I have a 99 model 200efi Merc and I believe my tach is not correct. The tach is a Faria tach and is set at 4 (10 pole alt) which I believe is incorrect, looking at the specs for the tach, I believe it shoud be set on 5 for a 12 pole alt. My tach has been showing me turning 6800-7100 RPMs and I dont believe I would still have a motor in one piece at those rpms. Will I hurt anything trying it on 5 vs 4 on the back of the tach?

 

[wrechin2]

Your engine is a 12 pole charging system so you do need it on the #5 setting as you suspected.

 

[TN444PSD]

Thank you James, I will give it a try today.

 

[Bomber 175]

Where do you check the setting, i have a 200efi merc 96 model my tach gives some high readings sometimes but shows i am turning 6200 rpms most times at WOT.

 

[TN444PSD]

Well, changed it to 5.... not the right setting, tach went well over 8000 and got stuck for a while, is it possible the tach is shot?

Bomber, look at the back of the tach, mine has a nob you turn with a small screwdriver and depress nob at same time.

 

[wrechin2]

#5 is the correct setting for it as it is a 12 pole system. It could also be a regulator/rectifier cauing issues. 99% of the time I find the tach is at fault. I have a "test" tach that I use to verify operation. I have both tachs hooked up and if your tach is the only one that acts up then it is proves your tach is at fault. That is about the only way to determine which it is.