Starboard engine idling rough

[Nikokrzynowek]

Backstory quick. I got this boat with the starboard engine completly seized up, never started it. Port engine ran just a ton of water in the oil. Rebuilt both engines got them in and running yesterday, just a quick start up they ran I shut them down. Went outside today to do a quick start up prior to taking them out to break in the engines and the port engine fired right up idled perfect no issues at all. Starboard engine tho fired right up then immediately stalled. Tried to crank it over quite a few times before it fired. Once it stared up it was idling really rough. Honestly sounded like the crank was going to fall out of the engine. Attached is a quick video of the engine running. I’m hoping someone on this form has had the same issue with their motor before and an easy fix. I’m leaning towards maybe a bad coil? And the engine is just misfiring or possibly injector. Any help would be appreciated. Thanks guy!

https://imgur.com/a/vqFOGKL

 

[Acard7]

Misfire is my guess. Kinda sounds like when I fog the intake on the MR1s when I winterize, Ofcourse they recover and run fine after it gets some air instead of fogging oil. How old is the fuel in the tank?…Even though port engine ran fine.. How old are the spark plugs? Oil level okay? Do you have YDS to plug in and test injectors and spark?

 

[Neutron]

Compression test to start

 

[Nikokrzynowek]

Both engines dont even have 2 minutes of them after full rebuild. I siphoned all of the fuel out of the tank and put fresh fuel. Plugs are brand new. Oil is brand new I put about 4.2quarts in. Bumped the stater with fuel pump fuse pulled to get oil into the engine prior to starting. I do not have YDS. I’ll pull plugs tomorrow and check to make sure there’s no fuel in the cylinders when cranking. Check the plugs and do a compression test. Is there any other way besides yds I can check the coils and fuel injectors to make sure their working properly?