i'm no refrigeration expert, although i did remove the crosby engine
drive fridge that the boat came with and replace it with an adler barbour setup. i've had it for six years now and it's run faultlessly, although when i first installed it it wouldn't run properly, i called adler barbour, they diagnosed it as a faulty control box
, and fedex'd me a new one the next day - free of charge.
since you're fridge was running perfectly for years and then suddenly changed cycling frequency i can only suspect two places; the thermostat, and the control box
. if you're happy with the thermostat, you might want to call adler barbour to see if they can diagnose the control box.
not sure if you know this, but the control box has a fault indicator light on it. it flashes fault codes when the box isn't working correctly. watch the fridge while it's running and see if the control box flashes fault signals when it stops. if it does, adler barbour (or your manual) might be able to tell you what the prolbem is.
another good source is richard kollmann, who occasionally posts here. he spent much of his life installing boat fridges in fort lauderdale
; he's retired now but still keeps active including writing a couple of books
on the subject. his website is kollmann-marine.com and i think you can ask him questions there and he will answer you.