Engine sync gauge vs. rpm's

[Dark Horse]

The other day while taking my boat on its maiden voyage, I noticed that when the engine sync gauge was right in the middle (synced) the rpm's were off on the two motors.
If I matched the rpm's the sync gauge was off.
As this is my first boat with dual motors I'm curious to which is preferred.
And how would I correct the difference if that is in fact possible?

[Midnightsun]

One is obviously incorrect. Unsynced engine will not have a smooth sound, more like a hum or moaning going on. Which sounded right? Sync gauge or tachs synced?

[Dark Horse]

Tachs synched by far. You could hear and feel the difference and that was how I ran it.
That Being said can I correct the sync to match the tach?

[mjk1040]

A mechanic told me years ago to go by the sync not the tachs. if your rudders are true straight, experiment in a open body of smooth water. If the boat veers of one way or the other your problem should be resolved as to which is true.