Yamaha F15 knock

[Bangstick310]

Hi, I have a Yamaha F15MSHC that has a knock. Motor sat for a long time and I was able to get it running with new parts.spark plugs, carb rebuild kit , thermostats etc. pretty much a complete tune up. Upon starting I have a knock. I’m not sure if it’s a stuck valve, rod knock or a fuel pump knock. I should say motor stalls and have a hard time keeping it running. I hoping someone can advise. I know nothing about this motor since I’m not the original owner. Where should I start. I have attached a video. Thank you in advance

video

https://youtube.com/shorts/ySc18gSumYc?feature=share

[ausnoelm]

I think you might need to do some basic investigation, remove the plugs and see if they look the same, do a simple compression test while they are out, a leak down test might be in your future as well as maybe some mechanical work, but, do the simple, non invasive stuff first.