I have a three year old pressure cleaner with a Honda GCV160 engine. Ever since it was new, it will only start and run with the choke fully choked. If the engine is hot and I even slightly un-choke it, it will surge and stall. I live in south Florida so I am surprised it even needs to be choked to start it on hot days. Is this typical of these engines and what would be a reasonable explanation for this strange behavior, even when brand new?

Although this engine does not have a lot of hours on it, it suddenly stalled today (just like turning the switch to off) after running fine for about thirty minutes. It restarted, ran for about 30 seconds, stalled, and will not now restart at all. Since it suddenly quit while running and does not even pop during starting attempts, I am thinking the magneto failed but I do not know for sure. The magneto core looks OK but there is a lot of rust on the iron and at least one lamination is starting to de-laminate. I am sure I am getting gas to the carburetor because I have good gravity flow out of the fuel cut off valve and I can smell gas when trying to start it. The plug had a lot of carbon on it but after wiping it clean it looks in good shape.