JayronDigital LCD Tachometer Inductive Tach Hour Meter Display Max RPM Waterproof for Most Gas Engine Marine ATV Generator Lawn Tractor Motorcycle (red)

I got this specifically to tune the carbs on chainsaws. I've used it on dirt bikes also. Functions as it should. I kept the packaging because it has the instructions on it and I don't use it every day so I forget.

Works perfectly. Made 10 wraps around spark plug cable, fired the blower up and worked right away. Very impressed. Stable readings after 1 second delay. IdleAt 2200rpm and full throttle was 5900-6000 epms.

So first of all the product does indeed work as described but the instructions are not all that great. If you continue to hit the set button there are 3 main settings. On the package there are instructions but they are vague. I have discovered that when you repeatedly hit the set button, you are left with 3 options and what they do; P=Pulse/R=Revolutions, (1P1R/1P2R/2P1R). Which is used for the difference between [2 cycle 1 cylinder~1P1R] , small engines with 2 cylinders that share one coil which sparks twice per revolution. "example v-twin/flat twin (opposing cylinder twin) engines"/[4 stroke, 2 cylinder 1 coil engines~2P1R] , and lastly any 4 stroke engine that has one coil per cylinder and only sparks once per 2 revolutions~1P2R]. So essentialy and simplified in MOST cases it would look like this.2 stroke, 1 coil = 1P1R4 stroke, 1cyl, 1 coil/magneto = 1P1R4 stroke w/stater, points, 12v coil = 1P2R4 stroke, multiple cyls, 1coil per cyl=1P2R4 stroke, 2 cyl 1 coil = 2P1R2 stroke, 2 cyl 1 coil = 2P1RSo to achieve the correct actual rpm, you must make sure it's seeing how many actual pulses are being supplied by the coil you are reading the rpms from. I hope this helps with the main settings and getting an accurate reading for the engine you're using this on. Once it is set one time for the engine you are using it on, it it's only used on that engine and or engines or the like, it will save its last setting. Which is nice for tuning a chainsaw, bike, car, go cart, ect... Other than the poor instructions, I feel it's very close to accurate based off using a scan tool and reading actual data on a car engine and comparing it to this device it was withing 5 rpms! I feel that's pretty impressive for how cheap this is.

Needed an RPM reference to tune a 2 stroke. Works great. Super easy. Recommend using the wire so you have 2 hands free to do the tuning.

Trying to use this for tuning chainsaws. On the low end, it seems to be off by 800 to 1200 rpm as far as i can tell. On the high end, wide open throttle, it shows numbers in the 3000s and occasionally will go up to numbers in the 6000s, when the chainsaws rpms are actually around 12,000. Really was trying to make this work since the price was right, but it doesnt feel reliable and the risk of damaging expensive saws is not worth it.

Literally just hold up to your spark plug wire for instant rpm read. I use this to tune my mowers, tractors and other small engine equipment. Really cool little useful gadget.

nicely made an worked as stated, used on my lawn mower an chain saw to set the correct rpms.

This maybe useful as an hour meter. But, the tachometer has limitations. First, the refresh rate is really low. So, you have to wait quite a while to get your reading. The other problem it's really frustrating is that the maximum rpm is not resettable. That makes it very limited for use as a tuning device.