Technical Anybody know what this sound is? I think I know......

Fired up my project to back it and clean the shop. Everything seemed fine untill I pulled it back in. Seemed to be missing and was making this knocking/popping sound through the carb. Didn't seem to be backfiring through the carb like if the timing was suddenly off though. The motor is a stock 8ba. Has always ran well since I put it together but besides running it for the break in and a few times a month to move it around it hasn't got alot of time on it. I'm thinking intake valve issue of some type but maybe someone has a better idea. I'll try to upload a video.

https://youtube.com/shorts/td-5pcDH4WI?feature=share

 

Always start with points on these engines when they suddenly run rough.

 

Thanks. Doesn't sound like an ignition issue though although I will certainly check them. I broke my compression tester so I have a new one ordered. Maybe that will tell me something

 

Keeper that came of the valve spring.
That's just a guess. Do a compression check.

 

First thought is a sticky valve. Marvel Mystery Oil in the fuel is your friend.

 

Definitely in the valve train.
Pull the intake.