diode for 12v bypass

i want to do a 12v bypass on my h runing a wire from the starter stud to the coil. anyone know a part number from radio shack or another store of what i need?
thanks
Gary

You do not need a diode for that.

Difficulties!
If your H has a saddle mount starter switch, it is tough to put a bypass on it. If it does, let us know and I can help get a solution. If it has a big push button you are in business with a diode. One good number is 276-1661 radio shack it is 6amp 50piv It will provide the starting voltage to the coil bypassing the resistor but not allow reverse flow to the starter. The stud on the switch that connects to the starter is correct, the one to the battery will not let it shut off. Jim

if you have the hard to get to switch.

in a hidden location, just install a simple push button switch.. momentary SPST.. 2 wire swoitch.. with contacts capable of 4a.

install tthe 2 switch wires ACROSS the resistor.

pressing that button while starting bypasses the resistor.

if you need 2 hands to start her ( feather choke, etc. then change that to a push on / push off latching switch.. hit it.. start.. hit again.

If your talking in the excite circuit the Radio Shack 276-1661 works very well and is way over kill. A pack of 4 will run your around $4 give or take a little

So much easier (Like Jim N was talkin about) if it has the saddle mount mechanical push start switch cuz you can buy them that are exactly the same EXCPET FOR ones used on like John Deere 620 720 etc HAVE AN EXTRA SMALL SIDE TERMINAL that's hot ONLY while cranking and you run a wire from it to the coils high input terminal so you by pass any ballast ONLY while cranking. BUT since you say starter lug it sounds like THATS NOT what you have cuz on those type starters and switches you cant get to any starter lug grrrrrrrrrrr

Of course as youre obviously well aware, a wire to the starter lug would appear as near a short so if you apply the coils voltage to it THAT AINT GONNA WORK LOL. If it were a pure solenoid operated starter, you could use like a Ford solenoid that has the extra small IGN terminal which is hot ONLY while cranking and run a wire from it to the coil THAT WOULD DO THE TRICK NO DIODE NEEDED!!!!!!!!!!!

Not cuz you need that many amps, but just since it will have bigger easier to manage and wire up stronger leads, Id look for a 10 amp rated diode with a PIV rating of at least 50 volts. If I recall correct theres gonna like a 0.6 volt drop across the diode.

Or use a switch (momentary push would be fine) to feed hot voltage to the coil while youre cranking her over or even a toggle if you remember to turn her off once started

Lots of ways to do this

John T

On my H , I used a diode taken from a junked alternator.