john deere 410 c barely turns over

[xixxixxixxi]

i have a john deere 410c tractor with backhoe. after sitting a couple weeks and a little rain, it wouldn't turn over. the starter smoked so i ordered a replacement and 3 days later with new starter it cranked right up. i then killed the tractor within the first minute by pushing to much dirt and now it won't start again. the new starter acts like the old one in that it barely turns it over and the cables start to get hot. i tried a different battery but same result. i tried a different ground and + connection and same result. i've had a similar thing happen before when i killed it under load but the fix was always to shut the hydrolic line on to back hoe which seemed to release the hydro pressure and make it easy to turn over again. this time that doesn't seem to matter.