73 Johnson 50ESL73 Charging info.

[bill lewinski]

I just got this yesterday for $150.00 with controls and tank, put it on the
boat and it starts and runs just like it came out of the factory. I already
replaced the impeller, points,condensor and plugs that came with it, all new
parts. My only question concerns the charging system. At idle it only
charges 8.5 volts. I didnt have my volt meter with me when I ran it.
Is this normal? I was told that these usually dont put out a full charge
until around 1/2 throttle. Any help would be greatly appreciated.

 

[tashasdaddy]

Re: 73 Johnson 50ESL73 Charging info.

100% correct, don't plan to run house lights, music, fishfinder, and trolling motor off starting battery. that charging system is only designed to maintain the starting feature.

 

[DJ]

Re: 73 Johnson 50ESL73 Charging info.

Volts or Amps?

8.5 volts indicates a severely discharged battery.

TD is correct, the capacity of the charging system is quite low. Maybe 3 to 6 amps at best.

However, a volt meter should show over 12 volts with the engine running.

 

[bill lewinski]

Re: 73 Johnson 50ESL73 Charging info.

Ok I guess I should have explained the whole situation. The battery I used
to start the boat was discharged, I had to jump it to get it going.
When I got back to shore I disconnected the battery with the engine running
and thats when I got the 8.5 volts off the cables from the motor. What I'm
concerned with at this point is if in fact the charging system is not
functioning properly would the motor stay running? I would always start
the trip out with two fully charged batteries in order to have cranking power
when necessary. Really appreciate the help.

 

[DJ]

Re: 73 Johnson 50ESL73 Charging info.

When I got back to shore I disconnected the battery with the engine running
.

That just killed your charging system. NEVER do that.

You probably "popped" the rectifier. Not a huge expense.

See link below. Scroll down to 50 HP (1973).

http://www.iboats.com/Johnson-Regul...8422356--**********.856873762--view_id.271366

 

[bill lewinski]

Re: 73 Johnson 50ESL73 Charging info.

Soooooooooooooo, the previous owner was probably telling me the truth
when he said there "WAS" nothing wrong with it. Looks like I just cost
myself about $40.00. As soon as the wife gets home looks like iboats is
gonna get my credit card number. Any recomendations as to which one
to get? Do you think it would be ok to run the motor tommorrow until
the new one gets here? Thanks for all the help!

 

[DJ]

Re: 73 Johnson 50ESL73 Charging info.

Soooooooooooooo, the previous owner was probably telling me the truth
when he said there "WAS" nothing wrong with it. Looks like I just cost
myself about $40.00. As soon as the wife gets home looks like iboats is
gonna get my credit card number. Any recomendations as to which one
to get? Do you think it would be ok to run the motor tommorrow until
the new one gets here? Thanks for all the help!

I'm an OEM guy, whenever possible. However, you'll be OK with any of them.

Yes, you can run the engine without it. As you are now aware, you will NOT be charging the battery so make sure it is fully charged before you take off.