tach, speedo, and battery issues

[Katsuo]

My speedo has been working intermittently since my boat's maiden voyage. Usually, after a shutting down the motor and restarting, it will begin working again, so I have never been concerned.

However, lately, my tachometer has been acting up. Sometimes, it reads too high. I'll be at about half-throttle, not even on plane, and it will read 6500 RPM's or more. Once I get on plane, it will stay at the same reading when I know it should be at around 4500 RPMs. If I throttle all the way back down (slowly) and go into neutral, it reads 1500 RPM's.

Either that, or the tach simply won't work at all. Yesterday, I made a run to Catalina Island (22 miles offshore and back, with plenty of stop/starts). The needle for the tach never left zero all day.

The other issue that cropped up yesterday was that battery one apparently lost it's charge. Once I reached the island and shut down, the GPS and all other instruments went dead. I was not able to restart the motor on battery one. I always alternate use of my two batteries, and never run in the "all" position.

Are these issues related? Any ideas where to start troubleshooting. I will consult my dealer as well.

[Putershark]

I would not think that the Speedo issue is related, but the battery going south and the Tach acting up could be... I would start looking for some loose ground wire or a alternator output issue for sure.

[Mud Runner]

It would help to know the make a model of the engine to help you. Is the speedo a mechanical or electronic model? The speedo normally get its' reading from a pickup at the base of the lower unit or from a pitot tube mounted on the transom. The tach gets its' signal from one leg of the rectifier/regulator. Chances are that the regulator is defective and needs replacement. Just make sure you check all connections for tightness as suggested before.

[Katsuo]

I have a Yamaha F115 mounted on my 2006 195CC.

[Mud Runner]

The first thing I would do, is charge the batteries and perform a load test on them. Some batteries don't last long and stop holding a charge. A defective battery can blow a rectifier. When hooked together through a battery switch, a bad one can pull the good one down. It's best to have an isolator so that you can charge both but current won't flow from one to the other.

After you charge the battery, take a voltage reading with a good digital voltmeter. Record the voltage and then start the engine. Take a second reading while the engine is running. This reading should be at least one volt more, if not one and a half more.

The most important thing is that if your engine is an '06, it's under warranty. Take it to the dealer so you don't give him grounds to deny a claim. You paid good money for it. You should also get a Yamaha factory service manual. It's saved me lot's of money when I do my own work.

Good luck

Here's a good digital, inexpensive tester.



http://www.harborfreight.com/cpi/cta...emnumber=90250

[Katsuo]

Thanks for the detailed advice.