Specifially an MTD that wont cut long grass – thoughts?

Grass is too long? Sorry couldn’t resist. Check the mower deck height has not dropped right to the bottom (some are adjustable) also is the cutter deck drive belt slipping? Does the blade need sharpening? More detail might help.

I have no details. It’s on eBay. “Will only cut very short grass”
I’m thinking the hydrstatic is knackered now

Steer clear of that one I would say
Hydrostatic is a pita when it breaks

Hydrostatic will only control the drive to the rear wheels, cutting deck will be driven by a belt from the [vertical] crankshaft under the engine.
The clutch on these is electric and as such either works or doesn’t.
I’d go with the drive belt needing replacing or they haven’t tensioned it properly (often done with a hidden lever that pulls the deck back.
Link?

OK, found it. Could also be cutting deck bearings or just dull blades (not convinced on that one though).

You managed to find it from that… Your eBay’fu is strong. Grey MTD

He says he’s done the belts.

“I’ve changed oil & belts a couple of times and replaced the battery a couple of months ago but haven’t had a professional look at it”

Buy another one, or use a brushcutter, it’s probably quicker