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Hello!
I have a 1978 Yamaha 40BR, which is now closer to a 40BE, as I have installed a electric start and rectifier to it now. Next point will be installing a cylinder head temperature gauge and tachometer. Installing a CHT gauge is simple and I have no questions about it.
Tachometer is fairly simple also but main question is do I need a special marine tachometer or would it be possible to install a standard automotive tachometer? Automotive tachometers use 12V signal and tachometer signal from my outboard is according to what I have read AC and might be higher than 100V. Haven't yet measured it with multimeter. Can standard automotive tacho for petrol engines understand this signal as long as pulse rate is set correctly on tacho or will I burn it due to higher voltage?
There should no question that a marine tacho from Faria would work as the manual http://faria-instruments.com/site_manuals/IS0012u.pdf says that connect a wire originating from the unrectified side of the alternator to signal terminal on tach. Tach signal on Yamaha 40BR is one of the two green wires coming from the lighting coil. The same engine was also sold as Mariner 40BE. This manual also notes on Mariner outboards that use a tach adapter 17461A9 but I have read that all that adapter really includes is a .33uF capacitor. So it should be ok as I install a .33uF capacitor between signal and ground terminal on tach.
Hopefully someone can help me with this marine/automotive gauge question.
Best regards
Ville from Finland
I have a 1978 Yamaha 40BR, which is now closer to a 40BE, as I have installed a electric start and rectifier to it now. Next point will be installing a cylinder head temperature gauge and tachometer. Installing a CHT gauge is simple and I have no questions about it.
Tachometer is fairly simple also but main question is do I need a special marine tachometer or would it be possible to install a standard automotive tachometer? Automotive tachometers use 12V signal and tachometer signal from my outboard is according to what I have read AC and might be higher than 100V. Haven't yet measured it with multimeter. Can standard automotive tacho for petrol engines understand this signal as long as pulse rate is set correctly on tacho or will I burn it due to higher voltage?
There should no question that a marine tacho from Faria would work as the manual http://faria-instruments.com/site_manuals/IS0012u.pdf says that connect a wire originating from the unrectified side of the alternator to signal terminal on tach. Tach signal on Yamaha 40BR is one of the two green wires coming from the lighting coil. The same engine was also sold as Mariner 40BE. This manual also notes on Mariner outboards that use a tach adapter 17461A9 but I have read that all that adapter really includes is a .33uF capacitor. So it should be ok as I install a .33uF capacitor between signal and ground terminal on tach.
Hopefully someone can help me with this marine/automotive gauge question.
Best regards
Ville from Finland
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