The engine has 188F on it and is 13hp. See attached image.
The Honda part number for the check valve appears correct. I think I'll try a more cost effective alternative first.
BTW - Whatever alloy material the fuel tap is made out of is rubbish. It had snapped off but still had enough thread to be useful. Removed old thread from tank and reinstalled - snapped off again while installing. Only had a tiny bit of thread left so wound it in as much as possible and glued it in with Araldite. The alloy appeared soft as if the fuel had weakened it somehow. It couldn't have been this weak at manufacture as it wouldn't have survived transport.
