yam 40 4str not charging

[nedoleboy]

gday chaps. ive got a yam 40 4str 2004 mod with 730 hours and recently the tacho and hour meter stopped working although the digital display shows 730 hrs and 0 (zero) revs.what i didnt realise was that on my sounder i have the voltage on screen and when motor is running voltage is around 14.2v, but the voltage was remaining at normal battery voltage of about 12.6 when running.i didnt realise until the battery was drained and would not crank the motor.luckily i carry a little 17ah battery which started it to get me home.
i went to the dealer who said get the batt load tested and check fuses .i got a new batt and checked all fuses under console and inside cowling. still sitting on batt voltage when running.does not seem to charge batt.
has anyone had something similar happen???? any help much appreciated.ned

[Noelm]

it would seem to me that the charging system has crapped itself! the tacho NORMALLY runs off this as well, so seeing as it has died also, it would appear to be dead and will need some Surgery to repair/replace.

[FNQCairns]

Really how can a dealer miss this! well he now has a battery sale on top of you coming back to get the problem actually fixed.....Yes be carefull don't run the engine any more, get a new regulator rectifier or just the rectifier depending on your engine fitted/tested, even then the stator can be damaged because it has run for a good while with nowhere for the volts to go.

Most outboard fires are as a result of this, a tacho when it stops working must be investigated straight away for just your problem.

How come the dealer doesn't know this basic outboard stuff:(

cheers fnq

[pursuit001]

hi mate sell it and buy a etec.
cheers
(http://my%20pictures)

[wiz]

hi mate sell it and buy a etec.
cheers

how does this help him ?????

[BM]

I'm with you FNQ, anyone who works on outboards, evne a first year apprentice will typically know that if the tacho stops working you have rectifier/regulator issues.

Think I'd be finding a new Yamaha dealer somehow.... Otherwise they might have you replacing the lower unit trying to find the charging problem....... :(

[trev1]

genrally the tacho, charging coils and ignition are all fired by the stator under the flywheel. The ignition is a seperate set of coils so I would suggest getting the stator and rectifier checked out. If it turns out to be only the rectifier, make sure the stator gets checked right out as well because ,as BM says, if it wasn't charging the battries, all that voltage has to go somewhere and would have been dissapated as heat by the stator possibly cooking the stator or its windings

[Scott nthQld]

Just do a simple test before you start spending vast amounts of money. Get a multimeter and test the battery terminals without the motor running, then start the motor (make sure you have water running through it), give it a few revs (don't know if thats how they are made, but every outboard I've heard of will only charge the battery when the revs are up a bit) and put the multimeter on the battery again, to test what voltage is going into the battery. If its anything less than 13V (motor running), then take the cowling off and test the alternator, it thats anything less than 13V, a new alternator is what you need, if the alternator is reading about 14V, then there's something wrong between there and the battery and should be easily fixed with some new wiring. If the battery is reading less than 12V without motor running, give it a charge and take a reading again (once finished charging), and another 6hrs-12hrs later. It the first test after charge is 12V and after 6hrs anything less, put a new battery on the shopping list.

[nedoleboy]

thankyou all for your replies but fnqld wins the prize.borrowed a workshop manual ...not factory but cover yam and merc off the 'E' shop.
had ac volts on the lighting coil and no dc output.will buy new rect/reg tomorrow and see how she goes.

gday wiz and pursuit001. you 2 sound like the 2 Etossers i go fishn with.ones got a 50 and the other a 90.the 50 has been towed back once.it was just a blocked fuel filter but it did have to be towed.just waiting on the 90 now.
i ran out of fuel about 100m from the ramp one day and they offered me a tow.but with the wind at my back i popped the umbrella and sailed majestically to the ramp.:P ned

oh the dealer.i was a bit taken aback when i asked to book it in and he told me to check all the basic stuff which was the 20a fuse under cowling and a batt load test . he was quite abrupt.prob having a bad day.anyway i'll go buy a new rect/reg off him tomorrow and see if hes any bettter.