ignition plate

kat-a-tonik

Petty Officer 2nd Class
Joined
Jul 27, 2013
Messages
123
I have a 1958 18hp Johnson, the ignition plate has a minute amount of side to side play in it, I'm guessing this should not be like this, I think this led to my flywheel loosening several times and shearing the flywheel key the last time I had the engine out.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: ignition plate

It is not uncommon for there to be some play in the mag plate.
That should have no effect on the flywheel shearing the key. Did you torque it to the proper spec?
 

kat-a-tonik

Petty Officer 2nd Class
Joined
Jul 27, 2013
Messages
123
Re: ignition plate

Actually I just tightened the nut tight, I will torque it to specs when I put it back together again, I cant find a flywheel key like the one that was on it so I am having one made by a machine shop luckily free of charge
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: ignition plate

Do you have a NAPA store in your area? They carry a brand of aftermarket parts called SIERRA, I think they make the proper key that you need. You shouldn't use just any old key, it should be specific to the marine engine.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: ignition plate

As stated, get an OEM key, no hardware store keys or the like. They will shear, guaranteed. Ensure taper is clean. Does the flywheel move fore and aft, or just wobble in the mag plate?
 

kat-a-tonik

Petty Officer 2nd Class
Joined
Jul 27, 2013
Messages
123
Re: ignition plate

Yeah, I tried NAPA they have gotten me parts for this motor in the past but they didn't have and couldn't get this particular key, it's an odd key I have never seen one like it, its a combination of a half moon key in the middle of a long tapered key, when I get the key back I will post a pic.
 

kat-a-tonik

Petty Officer 2nd Class
Joined
Jul 27, 2013
Messages
123
Re: ignition plate

The flywheel doesn't move, the ignition plate under the flywheel has a little play in it, the flywheel may have sheared the pin because I didn't torque the nut to specs, I just tightened it down.
 

kat-a-tonik

Petty Officer 2nd Class
Joined
Jul 27, 2013
Messages
123
Re: ignition plate

I have checked Marine Engine parts but the key they show that goes to this motor doesn't match the one that came off of it
 
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