Starter wire gauge?

[putback]

Can't find this in search. Can't find the amps on the starter and it's not wired so I can't check it under load. Do'es anyone know the original starter wire gauge or the amp draw on a '63 40hp Evinrude? While searching I also saw the term continuous run solenoid. I expected to use a common starter solenoid matched to the amp load. I'm just putting this basket case together so I want the right parts on the 1st try.

 

[DaleH]

Some manuals specify the peak amperage and continuous draw. I recall my V6 starters peak were > 250 (maybe > 300) and ~170 continuous. I sold the manual w/ the motor, so I could be off. But ...

An older manual for 75 thru 125hp (3/4 cyl engines) 2-strokes says 75 amps unloaded and 120/150 amps respectively loaded. Whereas a manual for my old 90hp 2-stroke says 65 amps unloaded and 200 amps under load.

Looking at that, I would say a safe bet is that the peak voltage, even if milliseconds, is up to a good 3X the continuous.

 

[putback]

Thanks, it would seem reasonable to calculate the wire gauge using 150 amps. Fact is I'm using the elect from a '63 40 hp on a '62 28 hp. Mounting it on a 16' alum mokawk runabout, apparently a 1959.

 

[DaleH]

Remember that for ampacity calculations, the length of the run BOTH ways needs to be factored into the equation, even though each run is a separate wire. Example, if had a worst-case load of 20-amps and the load was 6' from the battery, you would account for a 12' run of 20-amps.

Then ensure you have sized appropriately to endure any voltage loss, i.e., typically 3% or less for critical systems (nav lights, VHF, etc.) and 10% loss for other systems (house lights, etc.).