Have a 2003 Arctic Cat 400 4x4 auto. When I get to 25/30 mph it acts like it runs out of fuel. If you punch at a stop it doesn't bog. But if you moving and punch it it bogs. Something in carb.? Flushed bowl with carb. cleaner. Maybe need to take apart? Has 350 miles on it. Been garage keep. Help?

 

take your carb apart and give it a good cleaning. clean out the jets as well. you may need to rejet. your main needle controls 3/4 to full throttle and your needle controls mid throttle and your pilot controls idle to 1/4 throttle and you rpms screw helps the pilot circuit check your plug to see if your running rich or lean. also give your air filter a good cleaning. and reoil it and see if that helps

 

Do a search for "Air jetting"... chances are you are also over jetted (too rich), as that is the way the factory sets them up (less chance of running lean and burning a piston).... less warranty claims... good for the factory but not good for economy or efficient running...

 

While running at full throttle if you quickly decrease the throttle to 7/8 and it picks up or smoothes out then you need more air or a smaller jet...
Almost certain you will need a smaller jet the stock 150 is too big... or you can do the 'air jetting' that I posted and keep the 150 jet in.
If you don't do the 'air jetting' then you will probably end up with about a 142 to 144 jet in it.
If you have to pump the throttle to get top speed then most certain you are too big on the jet. Same as with running top speed and going faster with less than full throttle.