i am still struggling with removing the plug. My eventuality is removing the engine and head. (which is what the local professional jet ski mechanics advise)
But for now, i am attacking the left over ceramic and electrode that remain in the center of the broken off plug. I noted a posting online that claims you can use the combustion chamber pressure to "pop" the ceramic and electrode out of the engine. I have studied the sectional drawings online of the spark plug design. The claim makes sense because friction appears to be the only thing holding them in place.
I tried it. I used the battery to spin the crank for 10 revolutions. The ceramic and electrode have not come out yet, but i believe the process has merit.
Next, I will be using the proper size (and material) drill bit to remove half of the ceramic and electrode and hopefully break the frictional bond.
My plan is to use the combustion pressure to blow out the last bit of ceramic and electrode. I will then use a common extractor to remove the remainder of the plug. (the threaded metal)
Something worth noting in my opinion: During this process I found that removing the fuel by way of the top of the fuel tank, using a hand pump, is a very easy way to remove practically ALL of the fuel from the fuel tank.
On the top of the fuel pump is the fuel line connection (top left). The black plastic box is a snap on piece. Underneath is a "flexible" plastic tab, which when flexed, allows the fuel line to be easily slipped off.
Disconnecting the wiring harnesses will prevent the fuel pump from operating when you spin the crank.
i found this helpful photo on the internet