It mows ok for 2 or 3 feet, then stops mowing although blades are still turning
Clutch cable was replaced last year. The belt is not loose and the mower propels okay.
I am guessing that the clutch itself may be slipping. Is there anyway of testing this theory.
I dont want to replace the clutch and find out it may be something else.
Also, when I engage blade control I can move the blade by hand (it does have some resistance but not stiff resistance) and it makes a squeaky sound as I rotate the blade
Looks like this is a belt drive, so not sure what 'clutch' you are talking about. It's either loose or cooked . . . and looks like a belt is a whopping $11.32 . . .
Either you have been slipping it a lot starting the blade *or* it started to slip and was not noticed, overheated, and died . . .