Originally Posted by Rusty123
My Yanmar 2QM15
has a Faria tachometer with a magnetic pickup. It's not very accurate though (reads 2100 when engine
is actually at 2500). Not sure if calibration is possible, but since I'm in the middle of an alternator/regulator upgrade, I could easily switch to a tachometer with electronic input, and abandon the magnetic sensor.
Any reason to choose one type over the other? Is one more inherently reliable or accurate, for instance?
I believe it's not the sensor, but rather the Faria tach technology.
First, though, your tach is likely adjustable, in case you didn't know. There should be two adjustments on the back, one course (a range of flywheel teeth) and the other fine... so you can dial it in using a hand-held tach to calibrate. That said, our Faria tachs are therefore most accurate at 2000 rpms (the set point I used), not as accurate at 600 (idle) and 2600 (WOT) RPMs.
Second, Aetna Engineering makes electronic tachs that are said to be accurate to within 1 RPM
... and one version can use the same magnetic sensor you have. I know of an owner who changed his tachs from Faria to Aetna and he's been very satisfied.