I have a 1996 Merc 4 stroke that I want to get
an rpm reading on for the purpose of setting up/choosing
a prop. I have hooked a frequency meter up to
the tach signal. I also looked at it on my oscilloscope
to verify that the meter wasn't getting fooled. Seems to
be giving me a nice ~ square wave.

Now I have found some info on the motor that indicates
that it has 6 poles on the stator. Does this mean I get
six pulses per rev? or three?

I am getting just about 260 Hz at wot but about 95Hz at idle.


I am a bit confused as the motor should top out at about 5500rpm.

The 260Hz seems about right for 5200 rpm for 3 pulses. But
the 95 Hz seems to give me the right idle rpm (~950 rpm) for 6 pulses.


Any help?


Thanks


--

Almus Kenter
(617)495-7056


`` Pluralitas est ponenda sine neccesitate''
`` carpe per diem ''