3HP Johnson Two-stroke Outboard: flywheel removal

[Zack]

My friend and I are trying to fix a 1952 Johnson 3HP Seahorse two-stroke outboard.
It hasn't been running in easily twenty years.
Anyway, we gassed it up, sprayed some fogging oil into the cylinders, and then cranked. And cranked and cranked and cranked.
So we pulled a sparkplug and grounded it properly (with the outer electrode on the metal of the engine), turned off the light and cranked. No spark! And the air that the piston was pushing out with it's spark plug removed smelled like gas, so that seems to be alright. So it's a problem with the spark, right?
Well, that's what we figured, so the next step is to replace the plugs and wires. Replacing the plugs is easy, but the wires is another story, it seems. They lead from the spark plugs to deep underneath the flywheel. So we decided to remove the flywheel to get at the wires. That's harder than it sounds. We (with much difficulty) got the flywheel nut off and tried lifting the flywheel right off. No luck, it seems stuck on something. We knocked, we pried, and it still wouldn't come off.
So that leads to two questions:
a) is the replacement of the plug wires actually necessary? Could the wires prevent it from getting spark? Or should we just replace the plugs?
b) if we DO replace the plug wires, then how the heck do we get the flywheel off? Or is there another way to replace the wires?

And one other little unrelated question:
When you move the speed bar on the motor, it also rotates the whole coil/contact points assembly. Why is that? Is it some sort of manual spark advance mechanism?

[Dr_Davenstein]

You'll need a wheel puller to make sure you don't damage the magneto. It sounds like it may already be damaged though. If you do get it off be careful not to lose the little square piece of metal that should come falling out. You'll figure out where it goes if you look at the crankshaft.

One thing you can do to test the Sparkg plug, is to stick a screwdriver into the plug wire, hold the screwdriver by the handle, move the metal edge close to a metal part of the engine and crank it. If the plug-wire and magneto are both good, then you should see it arcing between the screwdriver and the engine block.

You might think I'm crazy for saying this, but if you see no spark at all, then you can hold the screwdriver by the metal part, and gently crank the engine until you feel a shock. If you get to the point where you know it should be shocking you... well, you know that either the wire or the magneto is bad.

Then, the only way to test the magneto would be to buy a new plug-wire and try again. If you do buy a new plug-wire, I'd reccomend trying it with the spark-plug in place before you do anything else becasue it might actually start. Who knows?

[Zack]

Cool. BTW, when you say "magneto", you're reffering to the whole contact-point/coils assembly?

Things to do then, are:
Perform the screwdriver-spark test to see if the only problem is the sparkplug. If it sparks, replace plugs. If not, replace wire, then try again. If still no, replace magneto components.
Sound good?
And to replace the wires I gotta remove the flywheel, then? How much does this puller cost, and how does it work?

Thanks.

[Dr_Davenstein]

You should be able to rent a wheel puller from Home Depot, Autozone, Westren Auto, etc...

I was actuall referring to the flywheel as the magneto. If it's the configuration that I'm thinking of, then the magnets are on the outer radius of the flywheel. When it spins, the magnets rush by the coil producing the spark. If all else fails, you can clean any rust off of the magnets with a piece of emery cloth and some WD-40... or another rust preventing oil-based solvent.

[Zack]

Thanks for the wheel puller tip - another thing, will I have to get a special type for this motor is it a one-size-fits-all type of thing?

About the magneto: Hmm, to me it looks like the coils are actually INSIDE and underneath the flywheel. Along with the contact points and capacitors. The flywheel is sort of hollowed out, see.

[Dr_Davenstein]

There are two types that I know of, claw type, and bolt type.

On the flywheel, if there are bolt holes in a radial configuration around the crankshaft, then you need the bolt driven type. The claw type aren't as easy to use, but it might be your only option.

Is there any way you could take a pic... or even a crude drawing would work.

[Zack]

VERY crude drawing. I'm not that informed on the whole ignition system functionality, so I might have left out a few components there.