Posted: Thu Oct 08, 2009 10:32am

Hi Tony I have a Yanmar engine model 3TN823-S. The problem that I have is the engine and the instruments are not connected together. They became seperated when the previous owner startad working on boat and didnot label any of the wiring. The engine runs fine with no problems all I have is a start button and the engine fuel cut off lever to stop. The instrument panal that I have came with the boat and has a volt gauge a temp gauge and an oil prssure gauge two lights one orange and one red which I gess are battery warning and ignition plus one ignition key. I have sent emails to Barrus Shire Engines asking for advice but they never reply. Any help or advice on where I can get a simple wiring diagram? Thanks Steve.

Posted: Thu Oct 08, 2009 11:29am

Dear Steven, by and large the circuits are much the same as on a vehicle EXCEPT everything not mounted on the engine uses a negative cable instead of the metal body/hull. If you only have one alternator there will be some kind of charge splitting device so it will charge two battery banks but the choice tends to be with the boat builder rather than the engine mariniser so I can not be much help about that. The red light is probably the charge warning lamp and it is normally vital in energising the alternator upon start up. The orange one is probably the oil pressure warning lamp. You will find generic diagrams for all the engine circuits on my website in the electrical notes. However you will have to work out how current is supplied to the engine circuits if there is no ignition switch. It may be by a rising oil pressure switch that turns everything on as the engine oil pressure rises. You will need to read the text to ensure you understand your particular alternator. www.TB-Training.co.uk (all on one line). Once you have studied the text, diagrams and your boat come back if you want any more info. Tony Brooks