High Voltage Yamaha two stroke 75 HP 2015 model

[Devdas]

Hi, I have two engines 75 HP 2015 model, bushing 25 fit fiberglass boat and I noticed the outcome voltage is reached 15 to 15.5 v while both engines are working and the same if using one while trolling. On full speed the voltage reached 17.5 from both engines, so I checked the battery which is new (70 Amp) and changed the Regulator/Rectifier and still having the same issue (not sure if its an issue or normal for two stroke engines). also I changed the stator but the voltage remain the same. all wiring and connection are ok.
what else I should check and change? Is this normal! what is the normal voltage for this type of engine.

 

[boscoe99]

What type of 70 amp battery? Sounds too small. Yamaha specifies a flooded lead acid battery with a minimum of 502 Marine Cranking Amps.

I would check the ground circuits from the rectifier/regulator to the engine wire harness. Ground connections of the battery cables at the motors also. But seems you have already done that.

While the voltage is on the high side, the amount of current available for the motors' electrical generation system is not enough to normally cause any problems. What problems are you having?

You could always purchased and install a non-Yamaha rectifier-regulator and give that a try.

 

[boscoe99]

What type of 70 amp battery? Sounds too small. Yamaha specifies a flooded lead acid battery with a minimum of 502 Marine Cranking Amps.

I would check the ground circuits from the rectifier/regulator to the engine wire harness. Ground connections of the battery cables at the motors also. But seems you have already done that.

While the voltage is on the high side, the amount of current available for the motors' electrical generation system is not enough to normally cause any problems. What problems are you having?

You could always purchase and install a non-Yamaha rectifier-regulator and give that a try. Or you can simply turn on a switch to a high load electrical component and that should drop the voltage.

 

[99yam40]

the reason Boscoe says check grounds is the motors generating system makes more power/voltage than needed, the RR should shed the excess voltage to ground to limit what is sent out of the RR.

I was wondering why he posted the same thing twice, but see he added a sentence on the end of the original in that second post, instead of just editing the 1st

 

[Devdas]

Thank you Boscoe99 and 99yam40. I will double check the ground circuits and see.​

I have no problem, all lighting and navigation devises are working ok, I just want to know if the high voltage will cause a problem for me or not and what needed to fix it if any. Can the battery last while charged 17.5 volt?​

 

[99yam40]

I would think 17.5 vdc would not be good on a battery over a long period, I am sure that is why Boscoe asked about what kind of battery that 70 amp battery is.
I also have no heard of a 70 amp battery before.
What are you measuring that voltage with and exactly where are you taking the measurement?

 

[boscoe99]

System double posted for me. I could not make a correction.

 

[99yam40]

System double posted for me. I could not make a correction.

I figured as much, the edit ability goes away quickly sometimes

 

[QBhoy]

is it tested as 17v at the actual battery and with a meter ? or is this read from a gauge on the dash ?