Engine Cranking but not Starting

[ClintonW]

Hi All,
Firstly thank you for letting me join this awesome forum!
I have a 3.0 MerCruiser inboard and can’t seem to get the engine to crank after sitting for 4months.
Battery good as have kept it charged, no corrosion on cables to starter solenoid, starter relay clicking when turning the ignition switch.
When turning the ignition switch, there is a fan type of noise coming from the engine but does not crank.
See video link: https://drive.google.com/file/d/1dmZ...ew?usp=sharing

Do you think the starter solenoid could be the issue or something else?
Appreciate the advice