RPM Gauge issue?
 

Not sure if this is normal and certainly does not seem normal to me but every time I shut the boat motor off the RPM gauge stays at 500-800 RPMs and will stay like that until I start her again next time. I don't remember this last year but I don't know for sure...

Is this something to worry about or nuisance issue?

http://www.mariahownersclub.com/gallery/file.php?n=5178

Re: RPM Gauge issue?
 

If it works I wouldn't worry about what it does when its off... :yes_grin:

Re: RPM Gauge issue?
 

Had the same on a previous boat. Explained to me that the potentiometer finds its own level but is zeroed when the ignition is switched on and signal received by the tacho. Could have been a mechanic trying to baffle me though :)

Re: RPM Gauge issue?
 

Try spinning the selector switch on back , and resetting to 8 cyl. Brew
If you do a search on tach or tachometers , you will find more info on the cause and process.

Re: RPM Gauge issue?
 

There is a weak magnet built into the air core meter movement that is supposed to return the gage back to 0 with no power. Does your gage go to zero when power is applied but the motor is not running? Do you have anything with a strong permanent magnet located near the tach?

Re: RPM Gauge issue?
 

Our Bass Tracker and my buddy's boat do the same thing. They work like they are suppose to when running

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Re: RPM Gauge issue?
 

Ha! I think your on to something... one of my Memphis 12" subwoofer is directly under the console... Ironically my compass has never worked but I am guessing that the subwoofer wouldn't let that work either. Interesting I just noticed the RPM issue but have had the Subwoofer installed there 4 years now.

Hmmm... Anyway to shield this from the sub without adding a lot of weight?

http://www.mariahownersclub.com/gallery/file.php?n=5184

Re: RPM Gauge issue?
 

As long as the tach operates normally with the ignition turned on...I would just leave it alone. It would be rather difficult to make a magnetic shield over such a strong magnet. You would need to use a good magnetic conductor like iron which rusts or even better a mu-metal alloy which is expensive and difficult to source. At least you know what's going on now.