Switching to a higher ma pack will not increase the spark unless the smaller pack has a dead/dying cell or the ignition box is extremely power hungry.
Don't forget the plug. I once chased a no-start on a Quadra. I had spark with the plug outside the engine but could not get it to pop. Ran through all of the tests; comp, coil, carb, and finally installed a new plug and it fired right up.
I would install a new plug and a new/known-good battery.