2003 Yamaha 4 stoke 115- shut off abruptly?

[tkess987]

Ran boat a good little bit last sunday.. Towards the end of the day running at around 4,000 rpms and but shut off. Then would not even turn over. As if the battery was dead?? I had a spare and worked fine. I later checked the battery and it was not low on voltage- not low at all? Maybe a bad connection, and I might have fixed problem when I recconnected to my other battery??

Will my engine run if I disconnect battery while engine is running? Or will it just shut off.... Not sure how it works. My first four stroke.

Thanks for the info.

 

[rodbolt]

Re: 2003 Yamaha 4 stoke 115- shut off abruptly?

will it continue to run if you disconnect the battery?
possibly but why do something so stupid?
usually they die and take out the rectifier with it.
the F115 needs voltage not only to power up the ECU,main relays,the 12v TCI ign but the high pressure pumps and fuel injectors as well.
that motor requires roughly 9 amps at a minimum of about 10v to consider running anything close to correctly.
the shutoff could be anything from a bad copnnection,low fuel rail pressure or a hydrolock.
if all you did was shift batteries to make it run I would carefully check/test all battery/battery switch connections.
check the ign fuse connection.
solid state devices dont like to have voltage spikes(power source dissconnected/reconnected) while in operation.
years ago with mechanical voltage regulators and low amp output setups in the automotive world an acceptable quick test was to remove the + battery terminal to see if the points could still operate the ign system and keep the engine running.
modern electronic TCI(transistor controled ignition) systems and ECU's that have 12 to 5V power supply systems dont like it at all and sometimes die suddenly when shocked.
if your concerned about battery charging use the service manual and a DVM with the correct harness adapters to check it.
wish I could tell you more other than carefully check each component,make sure the stop lanyard wasnt the culprit of the shut off and the restart failure wasnt due to it being left in gear.
dont laugh, it happens.

 

[tkess987]

Re: 2003 Yamaha 4 stoke 115- shut off abruptly?

Thanks for the help and the great info..

 

[tkess987]

Re: 2003 Yamaha 4 stoke 115- shut off abruptly?

I guess only asked if the engine would run without being connected to the battery, was to see if this engine would run off itself- that being the alternator/stator. That looks to be a big- NO

Would this mean if I were to ever accidentally kill the battery, and try to get jumped off. I not only have to get jumped, but wait to unplug jumper cables till battery is charged to the minimal amt. to run engine???


Thanks again.

 

[rodbolt]

Re: 2003 Yamaha 4 stoke 115- shut off abruptly?

no, if you need to jump start it follow the correct procedure for jumping a dead battery and proceed normally.
if you have the 6y5 digital package it will display battery voltage.
the problem with dissconecting a battery while the engine is running then reconnecting it is the voltage spike.
once the battery is dissconected the altenator "sees" it as a low voltage and tries to charge at maximum usually the voltage is now close to 15V.
when you reattach the battery,12.5 if charged, it acts as an inducive capacitive circuit. thats when you get the spark
if you have two systems at different potentials and hook them up you get an arc.
the battery will try to act as a capacitor while the wiring will attempt to act as an inductor and you will get a ringing effect.
thats when bad things can occur, not always mind you. some folks get lucky.
I usually dont.
but to answer the will it run question,usually not.
in fact most times a loose connection can shut it down,especially if the trim is used.