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1999 90HP 2 stroke AETO charging problem

S

Searider

New member
Hi guys

I am tearing my hair out with this issue as I cant seem to get to the bottom of it. Any help would really be greatly appreciated.

I have been experiencing high charging voltages whilst running the engine. The voltage starts off at around 14.4v but after 5-10 mins starts to creep up slowly until my volts gauge indicate 16.6v and starts flashing.

This is a true voltage as Ive measured the voltage with a multimeter across the battery terminals whilst running. My Garmin sat nav also confirms the voltage and my Icom radio has burnt out!

So far I have replaced the regulator/rectifier (no change), replaced the battery cable clamps ( not using wing nuts), replaced the battery switch ( was old and not making a good contact causing slow starting) and replaced one section of positive battery cable ( battery terminal to switch) and all of this has had no effect! Ive checked the engine earths etc and changed 2 batteries both brand new. One is maint free and the other is an Optima AGM. Yet still the volts keep creeping up.

Ive rigged up 2 brand new short test battery cables and wired them direct to the engine to count out anything forward of the engine in the console. It started very well with the stater running fast but yet after 10 mins the volts were back up to 16.4 volts (measured across the batt terminals).

Ive made up new battery leads but the last test showed it had nothing to do with the existing leads.

I have trawled the net for months now and have seen this problem coming up now and again but nobody posted a fix. I came across some saying that maint free batteries cause high charging voltages and should use a flooded cell old type battery but my maint free battery is a flooded cell type just non fillable so I cant see the reason behind this advice.

Some guys on other forums recommend you guys for help so many thanks for any advice you can throw my way

Mark
 
i am not a yammy man but if you have a rectifier only charging system this is a known problem with sealed or gel batteries....there is no internal discharge in those batteries....do you have a regulator or just a rectifier?..the owners manual for that motor is probably recommending a minimum 380 amp battery....i would try a 500 or so flooded cell battery...what you can do is put an extra load on the system such as running lights or a 12v cooler to see if it makes a difference..
 
did a little more research and i am pretty sure you have a unregulated system(rectifier only)....so this is a known problem...i also found where yamaha has a fix for it if you get to the right people...check with your local yammy dealer...if the dealer starts wanting to swap out rectifiers you are talking to the wrong person...do a search on ''yamaha battering overcharging'' and spend 30 min or so looking around and you will see a fix mentioned with very little specifics...something added under the dash...probably a load thats applied only when key is turned on...
 
i had this problem on a prior evinrude..there is an 2006 entry started by me if you do a search....read haffimans remarks and he explains what is going on...i never did fix the problem but helped it somewhat by going to deep cycle batteries...the fix was a regulator that i never installed..
 
Papyson - thankyou very much for responding - appreciate it very much.

I have seen the thread about a fix behind the dash - some Austrailains were talking about it but never divulged the fix? I asked the Yam dealer and he had no idea about the fix. My problem is this dealer is the main south coast dealer for my area (UK)

My Yamaha dealer told me the engine has a regulator and rectifier combined and sold me a new one which as you know did nothing to improve the situation but lightened my wallet somewhat :-(

I have seen various threads with info stating maint free and agms must not be used so when I get home (Offshore at present) I will buy a flooded battery around 500 amps but I dont understand the diffrence between a flooded maint free battery and flooded open cell battery - any ideas of the diffrence?

I am now not sure if my engine has a combined regulator and rectifier now. I have to admit whilst reading through my shop manual it does state it has a regulator/rectifier but in the data section does not tell me the voltage output I should see.

Many thanks for your time and help - a true gent :D
 
Found your post from Haffimans which explains a lot. Thing I cant get over is that Yam possibly dont fit a regulator to a 1999 motor! I can understand that on a much older motor but surely a more up to date engine would embrace modern electronic charging circuits?

Haffimans reply if anybody else is in the same boat as me;

"Let me try to make a VERY simple explanation of the different battery types. The old type (cheap)batteries lets the voltage encrease to a certain level, then You get a mini lightening that discharges the voltage to ground. It works as long as the amps pushed into the battery is not greater than that this internal discharge manage to balance it. This way the voltage is kept somewhat down. The more expencive 'sealed' batteries have a higher tolerance level and even a lower internal discharge rate that automaticly makes them keep the charge better (no intenal leakage). The disadvantage is that theese batteries in some cases (no regulator system) may build up the current to 17+volts which may cause other electrics/electronics to fail. The sealed batteries needs normally a regulator that charges up to 15Volts to get the battery fully charged. Even the 'regulators' used in the Evinrude/Johnson are not always good enough to use together with the sealed type batteries as they does not cut the voltage, just the amperage going to the battery. If the battry itself allow voltage to 17Volts, that is what You will get! The regulators used are so called 'clippers' that cuts off a number of pulses to limit the amps flowing, not the pulse hight to reduce the voltage."

Thanks again Papyson
 
from what i see on the web your motor may very well be rectifier only...the motor i had was a 94 evinrude and was rectifier only...it did have the place for the regulator up on the block though with the holes there and tapped to install it..the reason for that was the same block was used on a larger hp motor...this may be the case with your motor...yammy may have a regulator that would fit and use the same stator..the regulator will fix the problem if available..i went from the batteries i had on the evinrude 90 to a merc 60 with a regulator and they hold at 14.8 volts...
most dealers are hell to deal with on technical issues....they are sales oriented...and if you think you cant get answers on two cycles just wait to you go to a new 4 cycle efi with the computer driven bit...even the best technicians hook up to a computer and then the manufacturers support center looks at your engine via a link and tells the tech what to do...thats with merc and i assume all of them...i had the best merc tech i know show me the routine he goes through on even the simplest problems...he was poed because merc kept updating his disc for his computers and charging him for the updates...the end result is more expense for the boat owner...
 
Ive got a new battery (wet cell fillable via caps) on order. Ive gone for a 500 CCA as the table you posted shows minimum recommendation is 380CCA so hopefully going a bit higher wont be an issue. Ill let you know if it fixes the problem in a few days time as still offshore.

thanks again for your help :cool:
 
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