Blackmax Tachometer Poles vs. Pulses???

[dsiekman]

Okay, I am either real close to getting this nailed down or real close to losing my mind. Not sure which. Long story short, I have reason to believe the tach readings on my boat are wrong. It is an older Teleflex. Settings go from 1 to 6P. From what I understand, my Blackmax 200 is a 12 pole. Here's the question. Some sources I have found indicate that 12 poles equals 6 pulses. This is how my tach is currently set. Others seem to indicate that the motor is a 12 pulse and needs a tach that will read that high of an input. Can anyone straighten this out for me before I waste $100 on a replacement?

 

[dsiekman]

I'll add that at idle it seems pretty close to where I think it should be. However, I do not believe the top end number as at 5500 I get high 20's-30ish mph with a 23p prop and it will run all the way up to 7 (top end of tach) without issue. Either the prop is too small or reading is wrong...and I have a hard time believing the prop is too small.

 

[Chris1956]

6P is the correct setting. Tachs do fail....

If you an find the same model of Tach, maybe there is an application guide, and you can gain confidence that the tach is correct for your motor.

 

[SingleShot]

See if there is something in this doc that can help. View attachment TMTechCat-Instruments(v4_0)Tech Reference.pdf

 

[sam am I]

Perhaps redundant info as per the above link as I never clicked it however, 12 pole stator = 6 pulses/rev

 

[dsiekman]

Thanks, guys! Going to replace the tach and see what happens.