Any one know much about (faulty) analog tacho's

Another random act of pain from the gift that keeps on giving (the boat that is)

I have analog tacho's (factory) on a 250hp 4stroke Yam - have had no issues with previously until a few weeks back -
it now registers about 1500rpm above the "real rpm" - when you turn the ignition on the needle drops to zero but once started jumps up to 2200rpm (motor idling at correct speed)
I know they have a few switches on the back but before i start fiddling just thought i would ask if anyone has experienced anything similar?
cheers
Clint


Posts: 136

Date Joined: 03/06/09

Sounds like your motor isn't charging

Wed, 2013-01-16 19:42

My tacho has similar but not same symptoms. I'm told the tacho runs off the charging system - Evinrude but assume they're all similar. I had intermittent tacho till batteries ran flat. So, you need to check if the rectifier/regulator is charging or not.
I'm not an expert but what I've been told, and done myself to diagnose my problem, is to put an anmeter in series with your battery when the motor is stopped and also when running. Should show higher when motor is running. If not, need new regulator. Someone also tild me to check battery volts when motor off and also when running. Should be about 13.8V when running. Both tests work better when the battery is not fiully charged. PM me if you want more specific info.

 

pelagicyachts's picture

Posts: 1322

Date Joined: 23/02/11

mate thats awesome

Thu, 2013-01-17 08:28

mate thats awesome thanks
will give a try this weekend

cheers
Clint