525efi Tach reading high
 

2005 525efi, running on hose, idling just fine. The tach is saying anywhere between 2-3000 rpms. Smartcraft is reading normal 700-750 rpms.

What should I check, main ground on block? connections on the back of the tach? what else?

I take you have the Smartcraft SC 1000 gauges for the tach and MPH - just asking to make sure before think about it.

No, I have a regular tach AND a smartcraft sc 1000 guage which show rpms, water temp, pressure, oil temp, pressure, etc. Smartcraft is acting normal, the tach is not. Tomorrow, I'm going to check the main ground, and the connections on the tach.

AGI convertor box = analog gauge interface - for digital engines to convert digital signals to analog signals.



More info - Check all plugs in and check for dark and or corrosion issues at pins and or connections

Tach is PCM driven hence AGI box for convertor of digital signals to analog read outs.

Also grey wire and location main harness Pin 2.

Check for bad or loose grounds within the circuit., and check back side engine ground(s)

So you do not have this - especially for the TACH it can display both dig tach read out and the analog needle tach reading Just making sure. Click on link to see image.

http://www.blackdogmarine.com/images/79-889223K32.jpg

These are SC 1000 Tach and MPH gauges

maybe a good for whomever of the Smartcraft SC 1000 tach and MPH vid from Merc themselves. These are Smartcraft SC 1000 Tach and MPH gauges

Video link

https://www.youtube.com/watch?v=-jIzNPzxhX8

You must have monitor version 1.01 or 1.02 or monitor 2.00. I understand what you have now.

I would check the AGi convertor box and the connections could be POSSIBLE bad AGi box

Again AGi convertor box = analog gauge interface.

Yes, that is what I have, not the gauges in the link above.

Yes sir I had to think for bit of what you exactly had. Then the bulb went off in the head. I know what you have as I listed versions.

Check easy stuff first - grounds , wires . connections, plug ins, Any of the plug ins I would disconnect check closely and reconnect to see what happens. if no progress then possible AGI convertor or tach itself.

What kind of gauge? I have two boats with Fariah gauges and I have to tap the tachs at times to get them to smarten up, could very well be your issue.