Sometimes it takes off to top speed, sometimes it won’t go past 40. Sometimes it gets to top speed and bogs down to 40. This is with the accelerator fully squeezed. I have to fully stop and take off again. Does it about half the time. I changed the oil and spark plugs but it still doing it. The inconsistency is throwing me off. Engine sounds great, no noises and only has 160 hours on it. Any help would be great!