Yamaha 200 1994 overvoltage

[Omar]

Hello,
I have a 2 stroke 200HP Yamaha 1994. My Yamaha digital multi-meter indicate a too high charge voltage of 15.4-15.6V. I test the DC voltage with an external digital Volt meter and it indicate 14.9V.
I have 2 parallel connection gel batteries.
I think that 14.9 V is too high for gel batteries. Why the Yamaha digital multi-meter indicate 0.5V more? Is possible to calibrate it?
Thank for the Help
Omar

[boats.net]

No the volt meter can't be calibrated. This is what Yamaha list for battery requirements:

Yamaha recommends a Cranking-type battery for the outboard motor's use because it is most suited
to the application. A Cranking/Deep Cycle-type battery may be used if it meets the CCA and RC specifications
required by the engine. Be aware that a Deep Cycle or non-sealed "Low Maintenance" battery
may require more frequent maintenance (checking electrolyte level) than a Cranking battery. The
use of a Gel-cell or sealed Maintenance Free battery is not recommended because most are not compatible

with an outboard charging system.