I started another thread last week about replacing a hour meter on my mower, but before I send the $70 for a new meter, is there anyway to test the old one to make sure I don't have another type of problem. Its a one prong meter. I put a test light up to the wire with the switch on, and did not get anything, so now makes me wonder if it could be something else.
Bob
I don't have any specific experience with an hour meter, but in general:
To troubleshoot an electrical situation like this you need to verify if the input to the meter is on/valid, which is sounds like you have. If the wire coming to the meter is live with +12V when the switch is on that seems to be OK. Then test the meter itself by hooking it to a known good +12V source (direct to a battery, for instance) and leave it connected for whatever period of time the meter is capable of registering (0.1 hours?). The meter display should be on and should increase (i.e. by 0.1 hours) after that test. If both tests are successful then I guess I'm not sure what to look at next.
I haven't traced the single wire, but i did see in a diagram that it does go to the spark plug and wraps around the plug wire. I really hope that it was my tachometer since I have ordered a new one.
Some hr meters Get a signal from the coil / spark plug wire, that may be the case here. If so, your machine will need to be running for the meter to respond
One other thing I thought of... Since it is a 1-wire unit, check the ground that the meter is making with its mount. Even with good +12V if the ground isn't good it isn't going to complete the circuit.
I ordered a new meter for mine off ebay $59.99 free shipping. My old meter will light up if I remove it from the mower and shake it and play with it. I think it has a loose connection with the internal battery. Mine is a 2021 with 59.7 hours. Thought about buying a cheaper universal tach/hour meter. it wouldn't fit in the mounting hole. really don't want to coble up my mower just yet.
I did notice the meter has a date of March 3rd, 2019. It was three years old when I bought the mower in late August 2021. I had to wait all summer for a mower to come in.
I believe Bad Boy (and everyone else) drives the meter off the 12V electrical system exactly the same as was done in ancient times with mechanical clock hour meters.
So start by disconnecting the meter (2 wires, right?) and put a volt meter on the wires. I think you have to be sitting in the seat for the safety to let the engine run for there to be a signal on the wires. There are some digital meters which are not polarity sensitive, others are. Could yours be polarity sensitive, and wired backwards?
The single wire hour meters some speak of are retrofit hour meters. The single wire is wrapped around a spark plug wire. 10kV or so induces enough signal for the hour meter to detect.
I dug into the schematic of my Country Clipper and found the hour meter is driven by 12V from the ignition switch grounding through the low oil pressure switch on the engine. So the hour meter only runs when there is oil pressure.
So Bad Boy uses an hour meter / tach that has only one wire that goes to the spark plug and wraps around the spark plug wire to pickup the impulses. There is NO power / ground to the meter. It appears to have a battery internally as it is a sealed unit. AND they fail. I just had to replace mine at 2 years old and about 36 hours on it. My local BB dealer gave me a new one and tells me that they see a lot of failures of them.....go figure. I noticed on the BB site, that the replacement they sell for about 60 bux is different than the one I have on my machine (and the one they gave me). I've actually have it on my little genny now to put the hours back on it so its accurate to what was on my BB when it failed. The replacement is reading accurately for RPM.
In reality an hour meter is a toy to amuse the feeble minded and a tool to void warranties.
About 3/4 of the mowers I service have broken hour meters
Change your oil after the last mow of the season, before you go in for a beer .
Replace the oil filter with it or every 2nd or 5th year ( ie year ends with an even number or 5 & 0 )
Change belts as needed and do transmission idlers with every second belt and deck idlers with every 3rd belt .
Spindle bearings as needed because there is a finite number of times you can do them
After that 1 stroke of grease in all grease nipples on the first mow of every month, 1/2 stroke on deck & drive tensioners ( if they have a nipple )
Same time apply dry lithium spray grease to every place where 2 pieces of metal run against each other , expect to use 1/3 can each lube .
Do that and there is a better than average chance you mower will serve you well for 10 to 20 years
A very long air duster ( 3' to 5' ) is your best friend to keep the underside free from debris and while doing this you will notice things that are wearing out .
Yup the hour meter on my Grandad's IH Super M is a toy to amuse my feeble mind. To think of the hours he spent in that seat... am amused for hours.
There is a plethora of cheap junk Chinese hour meters available. Many won't sit in their packaging a year before the battery dies. But that is OK, changing oil by engine run time is a Conspiracy Theory brought to you by the Cheap Chinese Hour Meter Consortium.
At least one hour meter on Amazon has a replaceable battery. But at $25 it might break the bank vs the 2-for-$8 meters.
My Country Clipper hour meter times off 12V but has internal non-replaceable battery. Does not use a spark ignition sense wire.
