I have a 2005 Kodiak 450 and it wouldn't run at all because it sat for 6 years. I bought a new carb off Amazon that got good reviews, installed the jets from the original carb into it, and it runs really bad. I put a new spark plug in it, I installed a new petcock with filters in it and it can't stay running without the choke on a bit. I even installed a new intake manifold just in case there was an issue with the original one (I hear they crack easy). When you give it a little throttle, it just wants to die. I've included a link to a video of it running. You can hear it coughing and generally it barely runs.

Things I've done:
New Carb
New Fuel
New Petcock and filters in tank
New intake manifold

I'm a pretty capable person and am mostly familiar with 2 stroke racing engines but when it comes to 4 strokes, I'm completely lost. Can someone take a look at this and help me figure out what I need to do to fix this? Thanks for any info anyone has for me on this - I really appreciate it.

Here is the video I uploaded to YouTube:

 

I pulled the carb off and junked it. It was a cheap one off Amazon. Total Garbage. I grabbed the genuine Mikuni carb that was on it before and spent the time to clean it up good, all the jets and such. Put it back together and it was great. For anyone that’s curious, this Mikuni carb was not the carb that came on the machine. This is a Mikuni BSR33-P73 carb and it’s what Yamaha used then made their own model numbers. These carbs can be purchased for about $220. The Yamaha carbs are a bit over $400.

Anyways, the video shows exactly what happens when the carb is dirty and got buildup on the parts inside. Hope this helps someone out in the future.