2006 df225

[Capt. Craig]

What is the significance of the needle moving when the key is first in the on position with an analog tachometer? I was told it was an indicator of hours, but since I have passed 500 hrs. it now goes to 2100 then drops off. any clue???

[mike35292]

It says in the repair manual it is a indication of hours, but the number of times the rev limit light flashes is also part of it. I'm sure if you do some research online there is the exact way to tell.

[Harper]

Your tach indicates engine hours (10 rpm per hour) without any lights up to 540 hours, at which time it should be briefly indicating 5400 rpm. At 550 hours, the tach would read 50 rpm, and the rev limit light will flash once. The tach shows the hours (still 10 rpm per hour) plus the one rev limit flash up to 1040 hours, and so on. At 1050 hours the tach is again showing 500 rpm, and there are two flashes of the rev limit light. Each 500 hours additional adds one more flash to the light, while the tach reading starts over at 50 rpm every 500 hours above the xx40 hour mark.

For your indication of 2100 rpm, it should be indicating an hour reading of either 210 hours with no lights, or 710 hours if accompanied by one flash of the rev limit light.

Clear as mud, I imagine....