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

[WindSwept]

Alex,

I have #246 with the Westerbeke and I have added a 100 amp Balmar.  In my 
experience the alternator should not cause the rough running you are 
describing.

Someone else pointed out that the Westerbeke will run very rough if it is 
allowed to idle too low.  This is correct.  In my case, if the idle is set 
below 1000 rpm it shakes, rattles and rolls.  Well not quite, but you get 
the idea.

You may need to turn up your idle speed a little.  It is also possible that 
the person who originally installed the Barmar did not make needed 
adjustments to match the old tach with the new alternator which is the 
source for engine RPM readings.

However, whatever the engine RPM reading is, I don't think it should drop to 
50% of that figure even if the alternator is charging.  I suspect something 
else may be occurring.

I recently had the experience of my engine RPMs dropping from something like 
2500 to 1000 and surging back and forth while motoring.   Later I traced the 
problem to a dirty primary fuel filter.  If you haven't changed yours since 
your purchase, you may want to consider it, especially if you don't know 
when it was changed last.

Larry
C320 #246


----- Original Message ----- 
From: "Alex Krause" <al_exander at yahoo.com>
To: <C320-List at catalina320.com>
Sent: Saturday, July 08, 2006 12:17 AM
Subject: [C320-list] Rough idle on diesel due to Balmar Alternator?


> 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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