I have a Karcher power washer with a Honda gx270 engine. It won't start and I'm stumped. I've replaced the carburetor, spark plug, coil, on/off switch, oil sensor, oil change and a few curse words. What could be the problem?! I used it last fall with no issue and now nothing. The pump isn't seized, I got compression and spark. Please help me figure it out I'm going crazy!!