Pulling 16+ volts when running

[frillici]

I have a 1997 -200HP Mercury Saltwater. When I start the engine it charges at a normal 14 volts, but when it warms up it jumps to 16+ volts. I checked the volts with a volt meter, so I know it is not a faulty gauge. Also the tach jumps around - either shows correct RPMs or shows zero.

I assume it is a voltage regulator and if so are they hard to change and where are they located.

Also - could the tach problem be related?

 

[Barnacle_Bill]

Re: Pulling 16+ volts when running

Check all your connections to be sure they are clean and tight. Its possible you have a diode in your rectifier opening up when it gets hot. The tach runs off one of the leads from the stator which also feeds the rectifier.

 

[Silvertip]

Re: Pulling 16+ volts when running

The tach gets its RPM signal from the rectifier/regulator. If that's bad the tach will not register or it may be erratic. However, that behavior can also be caused by loose tach connections. Before popping for a regulator, check and clean the battery cables (both ends). Check the other ground connections on the engine as well. Salt water and electrics really don't like each other so corrosion is a potential problem.

 

[frillici]

Re: Pulling 16+ volts when running

Thank you both Ensign and Rear Admiral.

Where is the rectifier/regulator located? and about how much are they to replace.

I will check all the connections first and appreciate the confirmation that both the tach and volts are most likely a linked sympton.

 

[Barnacle_Bill]

Re: Pulling 16+ volts when running

Not exactly sure on you motor but you can go here http://www.mercurypartsexpress.com/PartsExpress/ProductSelection/ServiceParts/sphome.asp?CID=
to find it.