On Tue, 16 Mar 2004 bigfred@unm.edu wrote:
> Sounds to me like the tach is set up for a 2-stroke motor.
> See if there is a way to configure it for a 4-stroke motor.
>
> If the tach thinks it is reading for a 2-stroke, it will show the same
> number of RPM as there are sparks. So if the motor is spinning at 3000
> RPM, the motor (since it is a 4 stroke) will be sparking every other
> rotation of the crank or 1500 SPM (sparks per minute) = 1/2 motor RPM.
> Since the tach thinks the motor is a 2-stroke, it will show 1500 RPM.
Actually there is no difference between a 2-stroke and a 4-stroke tach.
Most all 4-strokes fire on both strokes, though they make power on only
one. Where the 2-stroke makes power every stroke. The reason I said that
it was most likely a 4-6-8 switch is because it reads it from the coil and
not a particular plug wire.
--
Scott H. Zekanis
zman@kungfumonkey.com
http://www.rod-o-rama.com
http://www.thehellbenders.com
1957 Buick Riviera Hardtop (2 dr., 364" Nailhead)
1959 GMC in Chevy Sheetmetal 1/2 Ton (235" Inline 6)
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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