battery or alternator

[dofunny]

Today I went out about 3 mile and stop the boat to fish. After 30 min I notice that my volt gauage had drop to 10 volt. The motor turned slow but it did start. So I didn't shut the engine off the remaining 4 hour of fishing. I have a 3.0L Mercruiser with a alpa 1 unit. Now if the alternator is bad why did the boat run for 4 hour.<br /><br />dofunny

 

[snapperbait]

Re: battery or alternator

What voltage are you getting when the engine is running? <br /><br />With no accessories turned on and the engine at a fast idle, the alternator should be putting out somewhere in the neighborhood of 13-14 volts.. If you don't trust your volt gauge, use a meter at the battery terminals with the engine running to verify 13-14 volts...

 

[flashback]

Re: battery or alternator

once started an engine can run a long time just off the battery even with no alternator, but like snapper says, check the voltage, may want to have the alternator checked by a shop, sometimes the diodes go bad and they drain the battery when the boats not in use.........If you have a multi-meter you may be able to check them yourself...also one of the simplest things to check for is the v-belt tightness, if it slips you don't get the full output......

 

[imported_Mike_M2]

Re: battery or alternator

Could be a bad regulator in the alternator, which would produce some current just not enough to charge a battery.

 

[metwrench]

Re: battery or alternator

Agree with Everyone else here, we need to know Voltages 14.5 is optimal, I also like to look at Amps on the back of the alternator ( alt output )bad Diodes can cause Low Voltage Output, Bad battery Can also Effect Low Voltages. How old is the Battery ? If you have a specific Gravity tester, test the electrolite Mixture in the battery and see where it is 1250 is Fully charged.<br /><br />But caution again: battery's can cause low outputs of the alternator.

 

[dofunny]

Re: battery or alternator

I check when I was out on the water the other day with my voltage meter and I was getting 12.7 volt before it drop to 10 volt. It be the regulator like mike_m2 said. I have know that to happen on car and trucks. But I'm new to marine type things. Gotta another question. How long should I flush the engine after I take the boat out of the water.

 

[dofunny]

Re: battery or alternator

How long do I run water to flush the engine after using it in salt or feshwater.

 

[Dunaruna]

Re: battery or alternator

Quote: [How long do I run water to flush the engine after using it in salt or feshwater.] <br /><br />For me, it happens to be the exact amount of time it takes me to clean and store my fishing gear.<br /><br />Aldo