I have a B & S 17.0 intek engine which has compression & fuel delivery but no spark. I've check the coil module clearance and have a new spark plug. The coil reads 4.6 ohms (I believe that to be the correct resistance) and I've also tried turning the engine with the plug out and held to a good earth point but there's no spark. I've tried this test with the kill-lead attached and also with it disconnected - still no spark. Can anyone help please?