I have a 19 hp twin cylinder kawasaki that acts like it is not getting gas after about 15-30 minutes, if you shut the mower blades off it will come out of it for awhile, but then it will still die without the blades on. I have tried replacing both coils, cleaned the fuel lines and filter and carb. Any ideas?

might take the fuel cap off when it starts acting up the cap might not be venting . also the fuil line might be cracked and sucking air,