alternator on 1978 70hp johnson?

[ritchie_bones]

is there a alternator on my motor to charge the battery? I have a 1978 johnson 70 hp seahorse 3 cylinder
reason is i took the boat out and the battery had no charge to turn over the motor and we had to boost it--this wasnt a problem last time i took it out

 

[Daviet]

Re: alternator on 1978 70hp johnson?

Yes, it has a charging system. The alternator is under the flywheel and has a rectifier bolted to the block. To see if ti is charging, put a volt meter on the battery and note the voltage, start the engine and run it at 1500-2000 PRM and see if the voltage goes up.

 

[ritchie_bones]

Re: alternator on 1978 70hp johnson?

i have a meter--im not sure what setting to put it on to test this-im not that familiar with meters

 

[Daviet]

Re: alternator on 1978 70hp johnson?

If it is a analog, needle tpye, does it have a 0 to 16 volt setting, use that. If it is a digital, it should have a volt setting, use that one. Make sure you use the DC volt settings, not AC.

 

[ritchie_bones]

Re: alternator on 1978 70hp johnson?

its digital-im taking it out friday-ill check that then