Anybody explain to me how the hour meter on the tach works? When I rblt the dasy, I used the old tach and cut it down to fit the panel I used. Everything worked fine until recently, but now the hour meter doesn't move. Granted the tach needle is a little "bouncy", but good enough for what I'm doing. As I recall, the tach is a rotating magnet arrangement. Don't recall how the hour meter is powered. Can I lube this with something? After all the time and labor involved in the new dash assy, would like to keep it, but really need the hour meter operative.
Not really sure exactly how the old mechanical tachos/hourmeters work. When they stop working & hours are still needed to be counted, best to just fit a 12V electrical unit to it. If you wanted to be real fussy you could earth it out through the engine oil pressure switch, so it counts true engine running hours & not the time the ign switch is turned or left on.
For the first time, in about 10 or 12 hours of use, the tenths digit advanced i number yesterday. That kinda indicates to me that the thing is still working a little. Think I'll open it up and give it a shot of Kroil - that'll just abot fix anything. Are the mechanical hourmeters designed to be accurate only at full rpms? Even on my new compact tractor, it doesn't record near as much time as actual run time. If that's the case, doesn't that make that reading pretty worthless, regarding total hours, service intervals etc?
The hour meter is a gear drive that has a nylon shaft connected on one end with a very small straight tooth gear to a gear on the drive cable and on the other end a worm gear that advances the numbers. Each number wheel has a small pin that will catch the next gear as it makes one full revolution. The nylon shaft can wear down and not turn or one of the dials will lose the small pin and not advance the next dial. If you need a tach, I have one I can send you. It's a trick to set the numbers to what you want but it can be done.
Thanks GWS. I'd like to have the tach. Mine advanced another tenth yesterday, so maybe it's going to work. Could be that the tenth advance pin is missing? I've been hearing a rattle that I thought was internal to the muffler, changed w/rpm, but noticed yesterday that one corner of the fan blades have a nick in them. Evidently when I had the rad rblt and hung back where it belongs, things are too tight. I know I need to replace the motor mounts, so assume that will fix the problem. Guess I won't be working on the tach for a while, but it would be nice to have it in hand.
PM me with your address and I will get it in the mail. There is a small metal clip at one end of the number dials that you can take off and drop the dials out. You can then set them to the hours you want and put it back in. There is also a hundreds dial on these tachs but it is blocked out by the front plate and is not seen turning. Keep that in mind when you put them back in after resetting. Don't force anything, it will go back together easily if everything is lined up.