Neighbors Troy Bilt Pony cranks slow then kicks back, think its the ACR?

[BackyardBrian]

Hey fellas, Brian again. Neighbor heard I been wrenchin on my X350 and asked if I'd look at his Troy Bilt Pony before winter. 17.5 Intek, bout 10 years old n 300 hrs.
Ran through everything you guys walked me through on my own stuff. Fresh battery, cleaned grounds, starter bench tests fine, strong blue spark, fresh gas, carb clean, valve lash set. Fires on starting fluid for half a sec then dies.
Heres the weird part. Plug out it spins beautiful. Plug in n the starter grunts, slows way down right before TDC on compression, sometimes kicks back hard enough you hear the bendix clack.
From what I been readin this screams sheared ACR tab on the cam. Pulled the valve cover n dont see the little pushrod bump before TDC either.
Am I readin this right before I crack it open? Whats the compression number im lookin for to confirm? TIA

 

[Bertrrr]

Your battery maybe weak , with no plug it will spin freely as there is no compression , make sure you have a good battery then see how it turn over for starting ,if it kicks off with starting fluid , it's a fuel problem not fire. Also too much starting fluid can make it kick back like your saying. I think it sort of advances timing because the flash point of starting fluid is so low ,

 

[ILENGINE]

Hey fellas, Brian again. Neighbor heard I been wrenchin on my X350 and asked if I'd look at his Troy Bilt Pony before winter. 17.5 Intek, bout 10 years old n 300 hrs.
Ran through everything you guys walked me through on my own stuff. Fresh battery, cleaned grounds, starter bench tests fine, strong blue spark, fresh gas, carb clean, valve lash set. Fires on starting fluid for half a sec then dies.
Heres the weird part. Plug out it spins beautiful. Plug in n the starter grunts, slows way down right before TDC on compression, sometimes kicks back hard enough you hear the bendix clack.
From what I been readin this screams sheared ACR tab on the cam. Pulled the valve cover n dont see the little pushrod bump before TDC either.
Am I readin this right before I crack it open? Whats the compression number im lookin for to confirm? TIA

If the valve clearances are set correctly, and I would double check. And still no decompression bump on the intake valve which in this engine is the bottom valve I would highly suspect broken ACR.