Frank, I have one of those laser tachs. They are very handy from time to time, as a shop tool. You just put a piece of reflective tape on whatever you want to get an RPM reading on, point the unit at it and you have a reading. It seems to be VERY accurate. It’s great for diesels, (that don’t even have an “ignition,” of course) for SHAFTS, and open flywheels. You can check the reduction of a transmission or gear box, by measuring the input and output speeds, and doing the math. One time, I found a small marine transmission was slipping, by doing this. I suppose it would be good on a non-planing boat, for an outboard. However, you have to hold very precisely for a few solid seconds, before it will get a reading. I can’t see trying to turn around and do this on a planing, bouncing boat. My particular unit also has a rubber cone on it, that you can physically engage in the top of a crank shaft, etc. and read RPM directly I don’t use it much, but when I need it, it is indispensable..
Long live American manufacturing!
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This reply was modified 6 years ago by
billw.