Yamaha F150 intermittent problem

[toddspano]

I have a 2005 f150 I started it fine it ran for a bit then cut out. It was not turning over or even any ptt. I checked all the fuses the are fine I took a voltage meter and I have battery voltage at the engine. It happened on monday and I disconnected the main harness and she fired up and now the same problem again. I have a good knowledge of boat motors just stumped on this one PLEASE any help will be greatly appreciated..

[rodbolt17]

double check all cable connections.
when you check batt voltage at the engine it MUST be checked under a load.
either cranking or depressing the trim switch.

[toddspano]

I have no ptt at all now from the helm even when the motor wants to start. Then out of no where she shuts down and wont do anything i.e. no key on power or ptt at motor and a continuous beeping alarm sounds and gauge goes dimmer then others.. Its on a twin engine set up so I have tried switching port key switch over to starboard but dosent change. I even bought a yds program it shows nothing because when the motor dies it looses all link threw yds..THANK YOU for any help..Todd

[rodbolt17]

you most likly have a bad battery cable or connection.
when it happens hit the trim while monitoring battery voltage between the starter solinoid and a good engine ground.
anything less than 11.5 indicates a failed cable/connection or battery.
also carefully trace the battery isolator wire to make sure its not chafed on the block.

[toddspano]

I went by and looked at the boat I think its the batteries he bought 2 deep cell batteries for the starboard motor and has a single starting for the port..

[toddspano]

I still dont have ptt from the helm its fine at the engine side switch. If I switch from port to starboard under binnacle starboard still wont move so its not in the switch.