tachometer for force 1987 125 (have tiny tach installed not sure reading properly)

dsiegrist91

Cadet
Joined
Aug 8, 2017
Messages
10
I installed a tiny tach on my boat and at ideal i am reading between 800 and 900 rpm i have not got a chance to get it in the water yet. I am wondering if this is normal to have a variance with these tachs. i have read other fourms and i saw that people have said to wrap 5 times instead of 3 and to also put it on the 4th plug wire to get it away from cd packs witch i did. i also see people say to not put it on a wire that has a coil but all 4 plug wires have coils on them. I have it set at 360 degrees (1 spark per rev) is this normal and can anyone give me a part number or link where i can purchase a 20 pole tach that i can actually wire the correct way. I am wanting to get a new prop because i am only running at 34mph at wot and its on a 17ft aluminum boat seems like i should be faster, but i want to make sure i am getting a accurate reading first so i dont destroy my motor. thanks in advance
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,924
For the TT to work right it should be running in the water.
The back pressure makes it run at the right rpm's.

Finding a 20 pole tach can be done, just look around.
Faria used to make them, but not anymore, might find a used one?
Teleflex Marine ?

Do a compression, spark test?
What rpm's at wide open?
 

dsiegrist91

Cadet
Joined
Aug 8, 2017
Messages
10
i had the motor in a 60 gallon storage bin full of water. i am taking the boat out tomorrow i have done a spark test i have spark on all 4 and the comperssion test come back at 130 on all cylinders. i am just not sure if this tach should read steady it seems like there would be some variance since its just induction
 
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