Engine Hour Meter Running Fast

[crquisto]

I have a Carver 406 with twin 7.4 Mercruisers. I keep a log when I cruise and noticed on the last two cruises of around two hours each that my port engine hour meter chocked up twice the hours of the starboard hour meter even though both engines have been used simultaneously. The starboard hour meter appears to be correct. Any ideas on how to fix the port hour meter?

[waybomb]

I'd be interested in knowing if there is an adjustment as well. I have a fast one as well. Not that fast, but fast.

I'm thinking getting a new one and just keeping the old one in case I ever sell the boat, in an effort to show why I changed it.

[tomschauer]

This is a question, not an answer, but will higher voltage spin them faster? I would think so.

[waybomb]

Voltage may or may not have an effect, but that's the first thing I checked.
In my case, the voltage as essentially the same. Within a tenth of each other.

[Viper]

Voltage will make a difference unless they're high end with a regulated power supply. Pretty sure they're calibrated for 12 volts so anything above or below that will affect displayed run time. Will depend where you're at in the charge cycle. If you're alternator is outputting close to 15 volts, the meter's going to run faster than 13 volts. Other hardware in the charge circuit will affect this output voltage like diode isolators. Running twice as fast though seems odd. I don't think there's an adjustment because they don't want anyone messing with them and intentionally slowing them down.

They'll run as long as you have the key in the ON position so always remember to leave keys in the OFF position. You can try hooking up a cheap hour meter in parallel and check the difference in a few hours. If the cheap one keeps proper time over your existing one, replace the existing meter.

[RGrew176]

On my Carver I have one hour meter that is running slower than the other. The port hour meter clicks over every 6 minutes 4 seconds. The starboard meter is slower at every 6 minutes 16 seconds. There is a 96 hour difference between the two. The other thing I noticed too on my boat is that the hour meters do not advance if one of the engines is not running. Both engines need to be running for them to click forward.

[Viper]

Qr Bbpost .....The other thing I noticed too on my boat is that the hour meters do not advance if one of the engines is not running. Both engines need to be running for them to click forward.

That's odd. I'm trying to figure out how that's even possible. Must be wired incorrectly. Once you apply 12 volts from one engine, the meter should run. Each should be wired into its corresponding RUN side of the ignition circuit. You'd have to combine both port and strb RUN circuits to get what you're describing which doesn't make sense or you wouldn't be able to shut off just one engine.

[RGrew176]

Qr Bbpost

Qr Bbpost .....The other thing I noticed too on my boat is that the hour meters do not advance if one of the engines is not running. Both engines need to be running for them to click forward.

That's odd. I'm trying to figure out how that's even possible. Must be wired incorrectly. Once you apply 12 volts from one engine, the meter should run. Each should be wired into its corresponding RUN side of the ignition circuit. You'd have to combine both port and strb RUN circuits to get what you're describing which doesn't make sense or you wouldn't be able to shut off just one engine.

For some reason that is how it is set up. Could be the original set up or perhaps one of the two previous owners changed something. As long as they work reasonably well I am satisfied.

[crquisto]

Well, folk, I believe I've found the problem and it's me. I left my ignition switch on a during the time in question after taking some fuel readings in port. Since I turn the batteries off when I leave the boat and only had them on for some periods of maintenance, I was saved from indicating several days difference in the meters. Checked it out the other day and they run at nearly identical rates. Thanks for your inputs. Still an education process.

[km1125]

Qr Bbpost Well, folk, I believe I've found the problem and it's me. I left my ignition switch on a during the time in question after taking some fuel readings in port.

Been there, done that!!! Took some fuel readings in the evening (which requires port engine ignition) then left the switch on overnight. +12 hrs on the engine!