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70 HP over voltage

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Aussie Pom

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My 70 hp when revs increase so does the voltage, will go up to 16v, have already blown 1 GPS sounder, put new rectifier conbination regulator on but made no difference, only way to keep volts down as revs increase is to turn lights on, prblem is I either forget to turn on or worse turn of when stopped. Any advice appreciated and thanks.
Richard
 
Hi Faxtbullet I have 2 x lead acid 12 volt normal marine maintenance free, have tried the old style type that you can top up and it made no difference, would you like to know the cca etc, I can get that later when I go to the shed.
 
There are only three parts for the charging system the stator, regulator and battery. The only thing you can do now is change the stator and possibly still have the same issue. What is the WOT rpms on your motor?
 
Do you have a tach that works properly? You size the prop according to wide open throttle rpms. You engine WOT rpms is 5000 rpms max actually between 4500-5500 rpms. The higher the rpms the higher the voltage it produces. If your revving too high it will greatly reduce the service life of the motor as well. Let alone your lucky it dont cook the powerpack also. If everything checks out but it still is overcharging get a 12 volt ice chest and run it while the motor is running to use up the excess power being produced and put a light on the dash to tell you when the battery is connected.
 
Now I understand and my WOT is 5200 rpm on flat water, and voltage verses Revs is aprox as follows 3500 rpm = 13.5V 4000 rpm= 14V 4500rpm = 15 V to 16v after 10 minute run 5000rpm = 16 to 17 volts,
 
Confirm the tach is correct one of those tach/timing lights work good for that. Around here you can just borrow one from the local auto parts store. FYI for best fuel economy and extended engine life just run the engine at max timing advance usually around 3/4 throttle. With the engine off in forward gear watch the trigger as you give it throttle at the point the trigger stops moving make a mark on your throttle lever. Keep it below 15 volts and you should have no problems.
 
Its not a RPM problem!!!!! This whole charging process depends on resistance in the system, check all the connections on the battery switch and grounds. DO NOT SWITCH while running as this will damage rectifier/regulator.
 
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Thanks to all for the advice, engine is a 1990 model and has been faultless until now with the voltage problem. Always ready to take on any advice from others, thanks again
Richard, from
Australia
 
Aussie Pom,voltage coming from rectifier/regulator is somewhat proportional to engine rpms,your voltmeter should not be reading over15 volts. Voltage is a product of ohm's law IxR=E I is current,R is resistance,E= voltage You have a high resistance circuit somewhere,thus creating higher current "Amperage","I", Higher current creates more voltage "E" "E" stands for Electromotive Force. Try looking this subject up on the web,you might get a better understanding of what's going on
 
I have to ask, are you very sure you have mounted the regulator/rectifier combination? All the behavior you describe is of an unregulated charging system.
 
johnygir, I have checked and double checked the system, disconected power to everything outside of motor to accessories except batteries, even put a old lead acid 12v from the car in, results are the same, put original rectifier back on and still showed same voltage, present rectifier/regulator obviously not working so will just stick to present system of turning lights on/off to regulate the V. Thanks for you effort and advice
 
WernerF obviously the regulator that I purchased is not working, as previously stated was hoping for somebody to have a quick fix or enlighten me to something that I may have missed, will put original rectifier back on and use lights as a means to keep V down, as you would be aware the OMC motos of the 80/90's did not have a regulator anyhow but somehow I never had this problem with any previos 90 HP or 100 HP only on this 70HP after 20 years. Non genuine and or modified parts are scarce here in Australia but I noted are freely available in the US. Thanks again for your help
Richard ( Aussie Pom)
 
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