Features:• 0-4000 rpm range
• Includes engine hour meter
• Uses alternator sensor
• For all Catalinas with Universal or Westerbeke inboard diesel engines and stock alternator
• For all later model Yanmar engines equipped with an alternator pickup.
• Automotive type "light piping" eliminates the "halo" effect around the edge of the dial that reduces readability
• Fog resistant design reduces fogging without the expense of a gas filled instrument at over $200.00 each
• Scratch resistant domed glass lens
Used on the following boat/engine combinations:
• All Universal Diesel engines with original equipment alternator
• Catalina 270 (Perkins M-20)
• Catalina 320 (Perkins M-30)
• Catalina 270, Catalina 309 (3YM20)
• Catalina 320, Catalina 355 (3YM30)
• Catalina 375, Catalina 385 (3JH5)
• Catalina 387, (3JH4)
• Catalina 400, Westerbeke 42B
• Catalina 400, Catalina 42 (4JH4)
• Catalina 445 (4JH5)
There may be other applications where this tachometer was used as well. It is likely this tachometer will work with a higher output after market alternator. Your alternator must be equipped with a pick-up "tap" on the back of the alternator. You must adjust the tachometer by first determining the pulley ratio and number of poles in your alternator. To assist in your decision and to calibrate to your alternator, refer to the table on the page labeled 337 provided below under "Read More". You are responsible for determining if the tachometer is suitable for your alternator before ordering. All sales are final for tachometers used on after market alternators.
• Nominal size: 3" diameter
• Bezel diameter: 3-3/4"
• Cutout: 3.4"
1) Our tachometers are adjusted to be approximately correct (within about 50 RPM) when installed on an M25XP with standard factory installed alternator and pulleys. Other engine installations may require an adjustment of the alternator range after installation of the tachometer to achieve reasonable accuracy.
2) A fine calibration potentiometer is under the sticker at the back (see "More Images" below). It is a delicate electronic device mounted to the far side of the circuit board with three soldered on contacts. The adjustment is accessible through a small hole in the board with three soldered on contacts. The adjustment is accessible through a small hole in the board. A watch maker can successfully adjust it without damaging it or pushing it off of the circuit board. Our experience indicates that mechanics are too ham-fisted and will break it every time. If approximately correct isn't accurate enough for your needs, you can attempt to adjust it using a jeweler's flat blade screwdriver (not phillips head). But once you remove the sticker over the calibration screw, the warranty is void and the tachometer cannot be returned.
3) For use with a Yanmar 4JH4E (typically installed in the Catalina 42) or a Yanmar 3YM20 (typically installed in the Catalina 309) when equipped with an alternator pickup: Set "Alternator Range" to "C" for it to be approximately correct. If you have a different Yanmar engine, this is typically the setting used. It is possible that at some later date Yanmar may change what is required.
4) For use with the Perkins engines there is no record that we could track down for the "Alternator Range" setting. Match your existing tachometer setting for it to be approximately correct. Refer to the table on page labeled 337 provided below under "Read More" for additional information.
5) Each tachometer is bench tested before it leaves. This leaves the indicator at a position other than zero. Once you install the tachometer, the indicator will return to zero when the engine is stopped with the kill lever before the ignition is switched off.