99 Johnson 40hp Alternator Output

Blue_Escape

Recruit
Joined
May 22, 2005
Messages
4
Hi,
just considering setting up a multi battery (start & deep cycle) charging system in the boat and wanting to know what the typical charging output from a J40TPLEEA would be. Also what is typical idle and WOT RPMs for this model?

Thanks
John
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: 99 Johnson 40hp Alternator Output

Alternator output is 12 amps at wide open throttle. Idle is about 700 and wide open throttle range is 4500 - 5500. Prop for the higher end. 5800 is even better. Just so you know, you will have to run for miles at wide open throttle to add any significant charge to the deep cycle battery. If you are long distances between spots it can help prolong run time but you should have an on board charger and plug into shore power to keep the deep cycle fully topped off.
 
Top