yamaha 40hp outboard not charging, cutting out....

[Marc]

my 40hp yamaha is no longer charging the battery and there seems to be no power coming from the engine when it is running, any ideas?

Second problem only happens once every month or 2.
Engine just cuts out as if there is no fuel going through and wont restart, when it does restart it will run for 2-3 seconds, maybe upto 10secs and just cuts out again. if i start the engine about an hour or 2 later will run fine again for weeks, sometimes months, any ideas?

Thanks
Marc

[jb123]

with the 2 issues and one being intermittent, sounds to me like you have a bad ground or electrical connection somewhere, start at your battery, then the rest of your ground points. if the cables are stiff theyre probably corroded and should be replaced.

[Marc]

ok, will check all the wiring and replace if necessary. where on the engine can i check to see if there is power coming from it when its running, (with a meter just to make sure its nothing else?)

Thanks
Marc

[Ken]

Marc,
Don't know what model you have, but in general on the Yamahas the lighting coil, which is part of the stator, feeds the rectifier/regulator assembly with raw AC power.
The r/r assy rectifies the ac and converts it to nominal 12 volt dc. This is the 12 volt charging voltage that goes to your starting battery for re-charge.
You can check the signal from the stator to the r/r assy to see if the lighting coil has failed.
If the lighting coil is doing its job, then the r/r assy has failed if it is not putting out 12 vdc. You can monitor the r/r output right at the battery terminals with a voltmeter.
Check all connections to the r/r assy, especially the ground wire.
Also, check any fuses that are under the hood of your motor. Should have at least one, and it will be somewhere in the range of 20 amp.
You need a Yamaha shop manual for your model - will give test points on the lighting coil and r/r assy.
Good luck [img]smile.gif[/img] ,
Ken K

[Marc]

ok thanks, my engine is pull start and has no electric start i think the model number is 40xhm but not sure on the engine is says 40xhm 66t L 205455 U
Thanks
Marc

[Marc]

i have just checked the voltage on my engine and on idle it seems to only be about 5-6volts, this i think is not right, any ideas?
thanks
marc

[Ken]

Marc,
The leads (12 volts and ground) that go to your battery from the rect/reg assy should never go below 12 volts while the motor is running.
Ken K [img]smile.gif[/img]

[Marc]

what do u think it could be, i tested the voltage at the battery on the leads and from the engine. checked all the wiring and they seem ok, also checked the earth and cleaned all the connections up.
any ideas
thanks
marc