1956 Johnson 30HP Coils?

[scuppers28]

I just purchesed a 1956 Johnson 30HP (RDE18), I didn't realize that it might be 6 volt and tried it with a 12V battery. Did I screw up the coils? Is there an easy way to check them. If they are fried, can I replace them with 12V coils? If so does anyone know the part #. Thanks

 

[petrolhead]

Re: 1956 Johnson 30HP Coils?

You mean you used a 12v battery to start it, it's an electric start yes?<br />You won't have done anything to the coils, the battery has nothing to do with the ignition, all it does is turn the starter motor.<br />The current for the coils is generated by the magneto.

 

[scuppers28]

Re: 1956 Johnson 30HP Coils?

Thanks petrohead, your correct, it does have electric start. Is this a 6v or 12v system?

 

[petrolhead]

Re: 1956 Johnson 30HP Coils?

All of the wiring diagrams in my manual (which covers your model) show a 12v battery.

 

[scuppers28]

Re: 1956 Johnson 30HP Coils?

A previous post by "oldboat1" in 2002 indicated that if it's a 1956 30HP it's a 6V system. My manual is the same as your only 12V. The starter is No. MDH 4001 9K is that a hint?

 

[petrolhead]

Re: 1956 Johnson 30HP Coils?

There is a mention in my manual of "early lower power starters", that could be a reference to 6v starters.

 

[Paul Moir]

Re: 1956 Johnson 30HP Coils?

I think the MDH might be a 6v one.<br />The true test is size. If it's much larger than 3" in diameter, then it's a 6v starter.<br />Credit for that bit of information goes to Iboats member Chinewalker.<br /><br />FWIW, my 28hp which shares the same block as your 30hp uses an MDO 4002 12v starter, which is just a smidgen over 3" in diameter.