putting new switch on old mercury

trying to put a new switch on a old merc 500 ols switch is labled a,e,b,d,f new switch is labled i,m,s, a m b c here is where i get lost i have 7 markings on my switch and only 6 screws. i believe a is accessory, b is battery, c is choke ,s is start, and i is ignition , now i have been told that the basic wires i need on my new switch is ignition start and bat. is this correct? i have tried s to starter silonoid b to battery and i to switchbox but when i connect the battery to the switch i get a lot of sparks and wire gets hot( not smokeing just to the touch ) i am useing 10 awg wire does this all seem correct or am i doing something wrong here also if i disconect the i from my switch then it turns over if i connect to the switch then it does nothing other then click click click also my motor is a 1973 merc 500

Re: putting new switch on old mercury

ok i think i confused a lot of people out there so heres what im trying to do i need to build a wire harness for my 1973 mercury 500 and heres what i did first replaced all wires on the motor one at a time as to not get them out of order the i put a wire from the battery to the b pin on my new switch then put wire from the switch box to the i pin on my switch then put wire from starter selinoid to the s pin on my switch when i try to start it my motor does nothing if i disconnect the i pin on my switch my motor turns over. so im at a loss as what to do now any help would be great

Re: putting new switch on old mercury

Ouch!! That ignition system doesnt work that way, hope you aint fried the switchbox or damaged the distributer. To make that switch work this is how it should be:
B= battery red 12v...................original color red
C= choke................................original color grey
M= ground..............................original color black
M= tan (original color)
S= start (runs thru neutral safety switch)...original color yellow

Re: putting new switch on old mercury

where do i need to get the ground from for the m from the battery or from the engine block also the other m(tan) is for my tach correct? i dont have a tach so does it matter what m pin i run the ground to i do have a book with a color schematic

Re: putting new switch on old mercury

I think there's a big difference between the old battery supplied ignition and the new stator supplied ignition.

The old way was to provide 12 volts to run.
The new way is to ground a kill terminal to stop.

If you mix them up, it won't run on the old way, and you'll permanently kill the switchboxes on the new way.

With a diagram and meter, you should be able to avoid trouble.

hope it helps
John

Re: putting new switch on old mercury

Here is link to wiring diagram for that engine, you will see it does not use 12 volts to pack, it just grounds it.http://www.maxrules.com/oldmercs/Wiring/1966ona/26A.jpg

Re: putting new switch on old mercury

ok so im lost do i need to supply or ground the switchbox i am thinking ground
whitch is where the ground to m pin comes in correct? sorry its a shame i can fix multi milloin dollar aircraft for the military but cand fix a 100 dollar boat motor

Re: putting new switch on old mercury

ok thanks for all the help people its alive i have:
b--bat
i--empty
c --choke
s--start
m--ground
other m--empty

woohoo its alive and well now just need to clean up rat nest of wire andfigure out the battery chargeing system then be done
again thanks for all the help

Re: putting new switch on old mercury

mike1245 said:

ok so im lost do i need to supply or ground the switchbox i am thinking ground
whitch is where the ground to m pin comes in correct? sorry its a shame i can fix multi milloin dollar aircraft for the military but cand fix a 100 dollar boat motor

Click to expand...

Thanks for the injection of confidence.........

Sometimes we can get so technically sophisticated that we can't deal with the simple stuff.......

Re: putting new switch on old mercury

yeah i guess so, ok next question is it safe to say that yellow wire from switch box is what kills motor when key is off and that yellow wire from switch box go to the other m pin on key switch? also if i look at it correctly red wire from rectifier goes to battery is this what gives it its charge?