[C320-list] Rough idle on diesel due to Balmar Alternator?

[Alex Krause]

I'm new to the C320 IA.  Bought hull 273 a couple months ago, keep in Long Beach CA, and am in the process of fixing all the little gremlins on the boat.  Wife and I really like the boat and I'm glad to have found this association.  
   
  Hull 273 (Westerbeke 30B3) has a very rough, loud, vibrating idle at times.  It is intermittent.  I think it has to do with the high output Balmar alternator that was installed.  At 80amps, which equates to 3 to 4hp (~10% of peak hp), engine idle is reduced as there is no automatic idle compensation like todays car engines.  Normal idle is 1150rpm, sometimes it drops to 600rpm.  After contemplating this for a while I've come to the conclusion that it must be the alternator.  I'm not certain this is the reason.  Has anyone else experienced this with their diesel's after installing a high output alternator?
To solve this I'm investigating an on/off switch for the regulator but I'd like to be certain this is the problem.
Alex
Coruna Cat #273  

 		
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