Case 580K with 4BT very slow to turn over

SO I have a 87 Case.
New alternator, 2 new batteries and new start all within in the last couple years.

I have a slow drain on the batteries so I disconnect them after I'm done using the machine. Last time I started it it turned over really slow and I had to boost it directly to the starter.
A couple days ago I tried to start it and same thing, but even with boosting directly to the start with my 1/2 ton it wouldn't spin over fast enough to start. Also I was spraying cold starting fluid in...

Case 580K with 4BT very slow to turn over

Case 580K with 4BT very slow to turn over