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1990 85hp yamaha battery gauge jumping

duckhunter1976

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I have a problem with my batte

I have a problem with my battery gauge jumping and wanting to charge more than it should.When i am running at top speed battery guage is reading 16 volts.I can hit the trim button and gauge goes back to 12 volts but goes right back up.When i am idleing gauge reads right between 10 and 12 volts.Even sometimes when running lights and depth finder light is on they want to flicker and dim and goes back bright when i hit the trim they really go dim and gauge also wants to jump when it is not over charging any help would be great on things to look for or to test .ANY INFO WOULD BE GREAT ????????THANKS.Jerry
 
Loose ground ? voltage regulat

Loose ground ? voltage regulator burnt should never go 16 volts if working does your tach work it gets its signal from regu any broke wires maybe mouse got behind panel and wires are shorting
 
I did a swap on engine from a

I did a swap on engine from a fiberglass bumble bee bass boat to a aluminum sea ark boat.I think the tach was working and maybe quit not for sure cant remember for sure or not.I do know the tach was working on the bumble bee.Where would a person even begin to start.How would u check the tach or the regulator to see if it was working? What wires would you check for the tach.No marks on the main wire or wires that goes to the throttle to the engine.Have not checked the wires form throttle to the dash.....
 
"get it out
turn it to a/c vo


"get it out
turn it to a/c volts
put it on the battery
start motor
if you see more than .8V, bad reg/rect"
 
Checked it shows to be putting

Checked it shows to be putting about 7.85 to 8.15 volts. Battery guage is sitting between 12 and 14 volts. What was the thing about the if the tach is not working.Im pretty sure it was working when i put the motor on the boat. Becuase i set the jackplate to it.Any more info would be great.Thanks for the help so far. Also someone told me i would haave to have a different gauge to check the voltage reg is this true or testing battery same thing right. Thanks...Jerry
 
"you need to test the battery,

"you need to test the battery, not the regulator

clean all the connections first"
 
Checked it the way u said and

Checked it the way u said and already cleaned the connections.That is how i got the readings.Started the motor and touch the tester to the battery only and got the readings off it.Anything else to check ? ? ? ? Thanks.....
 
Just checked it again. It was

Just checked it again. It was showing 7.85 and under clean more connections. The only thing it will read now is the 7.85 to 7.79 and that is it.Does this still mean it is a bad voltage regulator.
 
"Would that make the battery g

"Would that make the battery guage jump like that and over charge when running and charge right when idleing somewhat.What should guage be reading when idleing and running between 12 and 14 volts right.,?"
 
if u had it on a/c volts and w

if u had it on a/c volts and was over .8 volts
then you have a bad reg/rect

that is the best and easy test

if you want the factory manual i can email it to u
 
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