[C320-list] Inadequate Dedicated Starting Battery

[Hans Dose]

I know this doesn't directly address your issue, but one more thing to keep
in the back of your mind for anyone with a Yanmar 3GM30F... There is a
compression release on top of each cylinder.  Pulling one back before
cranking the motor makes it turn over much easier.  Then releasing it once
the flywheel has some momentum will make for an easier start.  And the more
cylinders you do that with, the easier it gets.  I've often thought of
making linkage from a straight piece of metal that I could tie a line to it
in case I ever had to do that alone from the helm.  They are a throwback
from when you could hand start the engines with a crank.  I did it a lot on
single  & two cylinder Yanmars with no battery when I lived in the Amazon
region of Brazil.

Hans Dose
1999 hull #569 "King's X"
Alamitos Bay - Long Beach, CA

On Tue, Dec 7, 2021 at 6:58 AM Onat Dogruer <onatdogruer at gmail.com> wrote:

> Hi Bob,
>
> I tend to be very cautious before commenting without knowing how things are
> wired on someone's boat. However, the issue doesn't sound like a wire gauge
> issue. Typically older diesels have a higher cranking amp requirement,
> recommended 450-500CCA min starting battery. Our 1998 has a Yanmar 3GM30F
> and starting surge is 283A.  The start surge is only for a second or two
> and once the engine kicks up, alternator starts feeding back. Our setup is
> slightly similar; we have deep cycle golf cart batteries but we always
> start on that bank. Aux battery serves as an emergency start.
>
> G27 batteries should be more than adequate; even a good G24 will suffice.
> The issue might be the 'new' battery may not actually be in good
> condition.
> Alternatively, there may be a loose terminal (even a slight wobble will
> decrease output).  If I were facing this, I would start by the simplest and
> check the terminals, go over the wiring of the house bank and of the
> starting battery, and lastly may do a load-test on the starting battery.
>
>
>
> On Tue, Dec 7, 2021 at 8:54 AM Bob Hoyt <rehoyt at gmail.com> wrote:
>
> > I recently installed a Duralast G27 Marine battery to serve as a
> dedicated
> > starting battery to go with my house batteries (4 six-volt golf cart
> > batteries in series). I installed it just forward of the starboard
> battery
> > compartment. The existing cables are listed as 4 gauge, so I thought they
> > were adequate.
> > With a fully charged new battery and either a cold or warm engine, the
> > motor will barely turn over. With the battery selector on all, it starts
> > quickly. Is the group 27 battery underpowered or do I need to change the
> > wire from the battery to the main switch and wire from the switch to the
> > starter motor to 2 gauge? Thanks
> >
> > Bob Hoyt
> > Hull 154
> > 1994 C320 "Ikigai"
> > Pensacola, Fl
> >
> >
> > --
> >
> > *Robert (Bob) Hoyt MD, FACP, FAMIA, ABPM-CI*
> >
> > *Associate Clinical Professor, Department of Internal Medicine*
> >
> > *Virginia Commonwealth University*
> >
> > *Richmond, VA*
> >
> >
> > *CAPT (Ret) USN*
> >
> > InformaticsEducation.org  <http://InformaticsEducation.org>
> > rehoyt at gmail.com
> >
> > Cell: 850-384-5235
> >
>