engine cuts out

[micron69]

good day all, just bought a boat with a 2008 V76 % salt water series Yamaha 225 cc when its running at very low rpms it cut out at times but starts up very easily and idles very well at 500 or 600 rpm , and we have notice it runs ruff at the lower rpms. They say this engine when running at lower RPMS drops some cylinders to make it fuel efficient ?
Thanks