Re: Onan generator difficult to start - electrician suggested a fix -

Mark Erdos

 Chris, here is what I did to resolve the issue.

I installed a 12v battery charger. When plugged into shore power, it will put a trickle charge on the start battery to keep it full.

When you next replace your start battery, get a larger more powerful  battery with more cranking amps. Get the most powerful battery that will fit in the space.

Hope this helps.


With best regards,





Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Tahiti, French Polynesia


On 4/11/2022 10:28 PM, Chris Paul via wrote:
Hi JP,
Thanks for your reply.
I think you are right. I will check the battery.
The main engine starts easily, so I thought it was the generator's problem.
I was not aware that the generator requires more cranking power. 

Hi Mark,
Thanks for your reply.
If I started the generator yesterday then it would start reasonably easily today.
If I did not start either engine for a week then the generator would struggle and sometimes not spin fast enough to start.
My method to start the generator was to start the Yanmar first.

So I am assuming the generator should start easily with a "good" battery and extra cables should not be required. 

Regards, Chris Paul (0427788800)

On Tuesday, 12 April 2022, 04:42:40 pm NZST, Germain Jean-Pierre <jp.germain45@...> wrote:

Both the main engine and the Onan are started from the same battery. Hence the note in the owner manual paraphrased as “ if the start battery is low, start the main engine”. 

Because the compression ratio of the genset is much higher than the Volvo or Yanmar. Look at the power output of the battery; it may be suspect. 


Jean-Pierre Germain, X owner ofEleuthera, SM 007. 

On 11/04/2022, at 21:08, Chris Paul via <chris__paul@...> wrote:

I have owned Glazig SM352 for about a year.

The Onan has always been much more difficult to start than the Yanmar.
This is particularly so if the starting battery has not been used for some time.
Do other SM owners have this problem?

Recently I spoke to an electrician and he suggested I connect the Onan to the Yanmar with 35mm starter cable.
This essentially doubles the starter cable size (for both engines) without opening the engine room seal. 
I am interested in the thoughts of other Amelians.

Chris Paul
SV Glazig
Currently in the bay of Islands, NZ

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