Mine has a battery holder on the left rear welded half on the hydraulic tank and extended out over rear. It is approximately 5” wide and 9” for and aft.
The lever was not designed to lock up. It was there to take pressure off the belt sow you can switch it on the high low pulley. Some owners take the pressure off the belt with a bungee cord for easier starting (I guess) but I never did. Machine was not designed for it and I thought it would...
Did you put some penetrating oil in the bolt running through the spring? I would try to break loose that bolt. I think it tightens the spring clockwise but first break it loose by trying to back it off and then lube it. Then draw it up on the spring. Do it on both sides! Let me know how it...
When the bar is up those plates “spring” under the bar to prevent it from coming down. The bar is pretty heavy so the springs have to be tight to have enough pressure to keep the bar up
There is a spring loaded curved steel plate at the lower end of lap bar on either side to hold the bar up. Tighten the bolt on spring so the plate creates enough friction to hold bar up. These plates can get warn thin and need to be replaced so you can put enough force on bar.
The tensioner is only there to loosen the belt so you can easily move the belt between the high speed pulley and low speed pulley. Neat and simple setup. That is it.