Voltage regulator/rectifier

[James004]

I have a 94' Yamaha 200 that has week spark on two cylinders. I am wondering if a bad voltage regulator can cause this.
How many volts should be being output to charge the battery? It is only putting out one volt if I disconnect the battery lead and measure what is being sent to the battery.

[boscoe99]

Voltage is measured with the regulator connected to a good battery. Should be more or less 14 volts.

Fix the voltage problem first and then proceed.

[James004]

Voltage is measured with the regulator connected to a good battery. Should be more or less 14 volts.

Fix the voltage problem first and then proceed.

Thank you Boscoe! With engine off. The battery is at twelve volts. With engine on it is 12.6V.

[99yam40]

a good battery should be 12.6v with motor running it should read 13-14

never disconnect the battery with the motor running

[James004]

a good battery should be 12.6v with motor running it should read 13-14

never disconnect the battery with the motor running

Thanks again! For some reason my battery charger (Schumacher from Advanced Auto Parts) will not charge a battery that is 12v or more. I need to get a new one.
With all the rain we have had. I have been blaming my bilge pump on running down my battery.

Yamaha sure does get good money for there parts.

[99yam40]

Thanks again! For some reason my battery charger (Schumacher from Advanced Auto Parts) will not charge a battery that is 12v or more. I need to get a new one.
With all the rain we have had. I have been blaming my bilge pump on running down my battery.

Yamaha sure does get good money for there parts.

are you sure the meter you are using is reading properly?

[James004]

are you sure the meter you are using is reading properly?

Yes I have several. I put the battery on my solar charger today and it went to 12.7V with engine off. 12.67V with engine running. The regulator failed the Ohm test. Instead of infinity you showed 7ohms and i think 19 on one of the other legs. I found a used one locally. I will install tomorrow.

[99yam40]

you should be measuring the input to the regulator also, like the service manual calls for.
but then that calls for a peak reading meter

[James004]

you should be measuring the input to the regulator also, like the service manual calls for.
but then that calls for a peak reading meter

I just received my DVA adapter today and did not get a chance to measure. However the stator was changed already. In an attempt to fix the week spark issue. Without the DVA I measured 19v or 29v. I cant recall exactly.
As far as the week spark goes. I believe it was due to two bad coils. I replaced one and that cylinder started firing. If I swap coils the problem moves with it. I have been told by two seasoned Yamaha mechanics that these coils don't go bad. But I cant argue with the reality that swapping showed. So tomorrow I will attempt to hunt down a coil. Anyone in CT have one for sale?

[Keithbaja]

How old is your battery ? 2 years its time for new.. That u can bank on..... And DONT use deep cycle
use cranking or dual purpose.. Read your owners manual.. (For gods sake)

[James004]

How old is your battery ? 2 years its time for new.. That u can bank on..... And DONT use deep cycle
use cranking or dual purpose.. Read your owners manual.. (For gods sake)

The battery is a dual purpose that is less than one year old. I put the new/used regulator on and now I have 14.25 volts!

However that did not resolve the week spark issue. So I put on a second new coil and all if good now.

Thank you to all of you for your comments!