Odd running behavior

[SammyMiamiCFBA]

I finally got the boat out on the water two weeks ago. And after being on the water... It just runs weird.... Seems to lose power and not stay running.
Here is a clip of it running today:

Any input as to why it seems to lose power would be great

I didnt get far from the dock before having issues with it and came back

 

[racerone]

Just open the low speed mixture screw 1/8th turn at a time.-----I think it will smooth out after that effort.

 

[jerryjerry05]

What's the rpm's in N ?
Should be 750-800 in gear in the water.
About 1100-1200 on the hose.
Compression?
These 2 cyl. motors can run on just one cylinder, make sure it's firing on both?

 

[Grub54891]

She's running lean, try adjusting as stated above. If ya can't get it to run better, you either have a carb/fuel issue, bad plugs/wires, or vacuum leak.

 

[jerryjerry05]

Try the starting fluid test: start motor, spray starting fluid around the intake side of the motor.
If the spraying makes a difference in the way it runs, then it's sucking air and needs work.

 

[puffitu]

Try to do as racer one said-had a similar issue and it cleared up

 

[Grub54891]

had one that had a bad crank seal, nothing I did fixed it till the upper seal was replaced.