DF 70 Charging Issues

[dynosaur]

New to the forum so I hope I'm posting in the right place. I have a 2005 DF 70 with only about 70 hours on it. The motor runs great. My issue is the volt meter was indicating about 11.8 volts then jumped to about 13.8 volts the other day. Today I ran the motor in the driveway and only saw about 11.8 - 12 volts when the key was turned on. Started the engine and the voltage dropped about .5 volts and did not respond to engine speed. Checked voltage at battery, static and running, and it matched my installed voltmeter. If I loosen the ground terminal on the battery the engine dies. This tells me the charging system on the motor is not working. Do I have a Regulator/Rectifier issue or an issue with the mag? I do not have a shop manual so I'm not sure how to test these components and I do not like to just throw parts at a problem.
Thanks for any help or guidance.

[Moonlighter]

It sounds to me more like you have a battery or wiring issue in the main battery cables. 11-12 volts with just the key on says bad battery to me.

Check continuity in the main battery cables and have your battery load tested before looking elsewhere.

As for the engine dying when the negative is loosened - these are electronic fuel injected engines that are controlled by an ecu, and removing the earth = no voltage to the ecu = no worky! Nothing like an old-school 2-stroke......

Remember, the more info you can give about what is happening and what tests, changes, repairs etc you have already done, the better to help forum members to assist you.

[dynosaur]

Thanks for the reply. The battery is about 4 years old. It charged kinda funny this spring when on a battery charger. It started out drawing no amps and gradually built up to drawing 5 amps over several hours. I left it on the charger for close to 24 hours and the amp draw barely came down so it could be a battery issue. Now as far as the charging system goes: 1. Shouldn't the regulator be putting out something greater than 11.8 to 12 volts to the battery even if the battery is shot? and 2. The ecm controlled outboards don't work like a car engine? I can remove the neg terminal on a modern car and as long as the alternator is working the engine will continue to run.
Not doubting you at all. Just trying to understand outboard technology a little better. Thanks

[Moonlighter]

You just proved yourself that the engine wont run with the battery neg disconnected.

Depending on alternator output, even a few seconds break in contact to the battery can fry the regulator. Spikes can damage other components such as the ECU. You may already have damaged your rectifier/regulator. I hope not.

Only a select few Suzuki 4 strokes - low hp models such as the 9.9-15hp are designed to operate without a battery.

Keep the focus on the problem, you already knew your battery was questionable. 4 years is not an uncommon lifespan for batteries, especially those not used all year round and kept charged up.

Suggest you get it load tested properly. Replace if necessary. Then test the voltage output again. Hopefully it will be OK and the regulator hasnt been damaged.

And also get those cables checked - it is not uncommon for them to corrode internally, seen it many times, and this can contribute to lack of charge getting to the battery.

[redlowrey]

New to the forum so I hope I'm posting in the right place. I have a 2005 DF 70 with only about 70 hours on it. The motor runs great. My issue is the volt meter was indicating about 11.8 volts then jumped to about 13.8 volts the other day. Today I ran the motor in the driveway and only saw about 11.8 - 12 volts when the key was turned on. Started the engine and the voltage dropped about .5 volts and did not respond to engine speed. Checked voltage at battery, static and running, and it matched my installed voltmeter. If I loosen the ground terminal on the battery the engine dies. This tells me the charging system on the motor is not working. Do I have a Regulator/Rectifier issue or an issue with the mag? I do not have a shop manual so I'm not sure how to test these components and I do not like to just throw parts at a problem.
Thanks for any help or guidance.

'''''''Your engine runs a fully transistorized ignition system, meaning it uses battery voltage to energize the coil primary not a magneto. It has a stator under the flywheel for battery charging, not a good idea disconnecting the battery negative, if it was charging it would have had high unloaded battery voltage. If it jumped to 13.8 volts it must have been charging at some stage, and the easiest way to test your battery connect up a digital multimeter to the pos and neg crank it over and see how low the voltage drops ideally not below 10 v0lts.

[dynosaur]

Good info. I will have the battery load tested and most likely replace it. Didn't know the system operated differently than a car system. I'm all about learning.
During cranking, the battery voltage would drop to about 8 volts (bottom of the scale) on the installed voltmeter.
One thing still seems odd to me. Why would the system not try and bring the battery voltage up. I see no voltage increase at the battery with the engine running regardless of engine RPM. In fact the voltage actually drops slightly. Could a poor battery cause these indications or is it indicative of a failed regulator?
Thanks

[dynosaur]

OK. I have some good news (I think) and some misleading data. While taking the battery out I found a 10 guage wire (hot side) with a 30 amp fuse had come apart. I think this is the charging lead to the battery. The fuse was good so I reconnected everything. The battery load tested good (but slightly low voltage 12.2 volts). I charged the battery for about an hour and a half and got the voltage up to 12.6. Reinstalled the battery, cranked the engine and volt meter was reading about 12.2. After about 30 seconds the volt meter started coming up. It would then swing between 12.6 and 14.4 volts. This was verified with a voltmeter at the battery. What is this data telling me? The battery, while testing good, is 5 years old (I re-checked the age). Could this swinging voltage output be a battery issue or is my regulator about to go? I think I will replace the battery anyway due to it's age.
Thanks

[dynosaur]

I replaced the battery and still have the same indications. 12.6 volts before start. Start the engine and the voltage is about 12.2. After about 30 seconds or so the voltage will begin to increase and start a random erratic swing between 12.2 and 14.5 volts independent of engine rpm. Any suggestions?

[dynosaur]

Replaced my Reg/Rec and the Suzi is back to life. Thanks

[Keithh41]

I have a 2006 Suzuki DF-70 with a check engine light and beeping. Dash voltage gage says 15 volts. The other day I pulled off the motor cover just shaking wires checking connections and when I put the cover back on and went out the lake no beeps no lights everything was great. Very next day as soon as I started the engine there was the blinking light and the beeps. I removed the cover once again and shook a few wires and checked connections but no luck. I did take the boat out for a quick run trying to troubleshoot a little and I noticed the voltage gage would drop from 15 to around 13 when I ever hit the trim. The check engine light blinks twice and than a beep than repeats, manual says bad rectifier, just trying to be sure it's a rectifier not not some simple short somewhere. Any thoughts or opions?