Strange issue..

[Phildoo]

Have an engine that has recently started a baffling problem. Its only running on one cylinder when its cold. Went for a test run today, same issue. thought it was plug for awhile but its not, it simply does not fire on one cylinder...so what I do is just keep on running it and it will come to life in 20-30 minutes of WOT. I was thinking it was electrical by not giving spark to that cylinder, so I stopped, changed the dead plug out and even swapped the plug wires..still dead...just kept goin, it came out of it eventually and gps'd at 52.
Compression is 150/150
Any ideas?

 

[Dr Honda]

I would check the carbs. If you aren't spraying fuel into that jug... then you aren't properly transporting oil either.

When the problem happens... is the sparkplug wet?