Suzuki battery drain

Joined
Nov 25, 2008
Messages
16
Please help.My 1999 Suzuki 40 hp four stroke developed this problem during the last fishing trip:received low battery warning from the GPS.I found the battery almost depleated after 4 hours running,recharged the battery,got 12.70v,hooked up starter cable,voltage droped to 12.40.Motor started fine(about 250 hrs on it).At idle it show 12.10 at battery terminals ,at 2000rpm ,voltage fluctuated between 6 to 8 volts.
Thank you for any help.
Vinson.
 

smartcaddie

Cadet
Joined
Nov 25, 2008
Messages
14
Re: Suzuki battery drain

well to be honest with you it sounds like a voltage regulator problem. but it can also be a number of things, outboard ignition systems are composed of a stator, tigger, voltage regulator and ignition coils and in some cases a main computer(im sure your engine doesnt have one). these four/five things work together to start the engine and keep the battery charged.. do you know how old your battery is?
 
Joined
Nov 25, 2008
Messages
16
Re: Suzuki battery drain

well to be honest with you it sounds like a voltage regulator problem. but it can also be a number of things, outboard ignition systems are composed of a stator, tigger, voltage regulator and ignition coils and in some cases a main computer(im sure your engine doesnt have one). these four/five things work together to start the engine and keep the battery charged.. do you know how old your battery is?

Thank you smart caddie,i forgot to mention the battery is brand new.
 
Joined
Nov 25, 2008
Messages
16
Re: Suzuki battery drain

Bad Connection?

Les

Les, you are right,while removing wires from the rectifier ,i found one black wire slihtly loose,to be honest,i didn't think it was the culprit at fisrt,i reconncted all the wires,no corrosion found after inspecting them.
I started the motor and found the voltage to be at 12.50 at idle and 12.80 at 200rpm,no fluctuation,i left the battery connected ,the voltage was down a bit after 12 hours,hope this is normal,i will check the battery voltage again in the morning.
Thank you.
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Suzuki battery drain

A fully charged good condition battery should show 13.2 volts. In order for the alternator/generator to maintain the battery it needs to deliver in excess of 13.2 more in the order of 14 plus. The indications are that iether the regulator or the alternator is not putting out the neccessary volts. A bad connection or a bad battery can give similar symptoms.
 
Joined
Nov 25, 2008
Messages
16
Re: Suzuki battery drain

I stated that i found a loose black wire from the rectifier,it is the engine electronic control module.(the black box about 1x4x6")
Anyway,i still have the draining problem if i donot disconnect the leads from the motor,(about 1.4 v a day),with the new fully charged battery it shows 13.6 volt,at idle it shows 12.25,1800 rpm,it shows 12.21,i will try to run the boat one day to see what the system put out at 5000rpm.
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Suzuki battery drain

The motor is drawing current when running. That is normal. You are not getting charge.The regulator/rectifier is similar to an automotive unit in function. When one or more of the four diodes fail they short out and you get no charge. Also current from the battery finds its way thru the diodes and the alternator coils and you will find that the battery goes flat if left connected. You can put a test meter on DC amps and connect in line with either pos or neg battery wire. DO NOT try to start the motor. This will blow the meter. Disconnect the regulator and see if the draw goes away. If it does, replace the regulator.
 
Joined
Nov 25, 2008
Messages
16
Re: Suzuki battery drain

I appriciate all the help i received from this forum.
I look up the service manual Iboat carries,i don't know if it will be of any help to me(i had a 2 stroke Suzuki,i have the same service manual for it but i found that it was not detail enough),it is hard to get one from Suzuki.
I cannot locate neither the regulator nor the rectifier on this motor.The rectifier from Iboat ($50.00,one from Suzuki is $130.00,i don't if they are the same but Iboats has only one for all Suzuki,i don't see anything similar on this motor.
Thanks.
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Suzuki battery drain

Go to brownspoint.com and look at parts. You will will find all the drawings for your motor.
 

rbstewart

Cadet
Joined
Sep 8, 2008
Messages
13
Re: Suzuki battery drain

You can get a service manual for this motor at a Evinrude Dealer. In 99 the Evinrude 4 strokes were Suzuki 4 strokes with different decals. I have the same motor and use this manual. The ERude part # for the manual is 787061. You can also get parts from ERude dealers for this motor. It is the only 4 stroke 40hp available from ERude in 1999. They won't necessarily be cheaper, but may be easier to get .... fyi.
Brownspoint is an EXCELLENT Suzuki parts resource...as has been said. Great people and VERY helpful.
 
Joined
Nov 25, 2008
Messages
16
Re: Suzuki battery drain

Thank you for all the help gentlemen.After $160.09 and 12 days of waiting,i got the regulator/rectifier from Suzuki,my volt meter shows 14.45 at idle.battery voltage remains constant when cable leads hook up or disconnect.Problem solved thanks again.
James R mention about getting drawing for the motor,i like to know how,i could not by the regulator from them because they want part number.
Happy Holiday .
Vinson.
 

Poorman

Cadet
Joined
Jun 21, 2008
Messages
15
Re: Suzuki battery drain

This reply applies to overnight battery drain. I noticed you made a statement of having a GPS. If by chance it is a Lowrance, my question would be did you wire the power supply for the GPS through a on/off switch. If not it will do a constant battery drain.
 
Joined
Nov 25, 2008
Messages
16
Re: Suzuki battery drain

I have a Hummingbird GPS/fishfinder,that is the only accessory that connected to the cranking battery,the rest to the deepcycle battery,i always removed the GPS/fishfinder and the trolling motor fishfinder after every trip,i also have a cut off swicth for the trolling battery(i also use it to run the mule to maneuver the trailer)
 
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