can not start generator

gennie cranks and runs ocasionally. It seems as if it just runs when it wants too. I am on number 5 starter or is it 6 or seven. Replaced a couple about a year after I got it. Two Generac starters and then they gave us the number of an aftermarket one and those were lifetime replacements. It started more than not for a while then a couple of more starters. Put one in a year ago and it never did start all the time. Did ok for several months and I was running it every couple of weeks, now we're back into the old cycle of I'll run if I want too, otherwise I'm gonna turn over slowly and not start.
At least my after market warranty is covering the whole cost now.