Changing to glow is not only the weight issue. My Poulan 25cc with glow has more power, starts easier, idles smoother then with magneto. Other issue is that the Poulan 25cc has very weak magneto support (the coil can vibrate 0.5mm up and down, so the gap between the coil and the flywheel must be big enough to prevent striking. With glow plug the coil can go away (I think you still need flywheel for the boat as the boat prop does not have as much inertia as a plane prop).