Jimmie,

I am not a generator guru, but I have experienced hard starting. That issue related to the generator in our first coach which had a Kubota engine. The present generator has a Yanmar and has been an easy starting generator.

After a period of non-use our Kubota powered generator would crank a long time, sometimes tripping the breaker as you describe. The problem was associated with fuel evidently flowing back out of the generator fuel system. It always would act like I had just changed fuel filters. My "fix" was to put 12 volts to the fuel pump leads. The fuel pump would click rapidly and as the fuel flowed and pressure built up the clicking would become labored and eventually quit. At that point if I initiated the start cycle the generator would fire right up with minimal spinning.

I did this procedure just prior to every trip and throughout our trip or travels the generator would fire up and run easily.

My guess is there is a fuel line check valve that was leaking. But I don't know that for sure.

On my current generator I had a fuel pump fail, so I would not rule out a weak or failing fuel pump.