Electric wet tile cutter running off

[barnfields]

Without seeing it , it would be hard to say what the issue is.
Have you placed a full tile against the guide stops, then push up to the front of the wheel so the tile just touches the side of the wheel. Then slide it through to the end to see if the wheel is away from the tile at the end of the push ?

I haven't tried that. It looks as though the table guide is set up wrongly. I have been concentrating on cutting the tiles free hand as Sir Ramic suggested. That needs a bit of tidying but I've managed to get some tiling done.
Thanks for all your help guys.