"you can go a little bigger in size."
No No NO NO NO NOPE! Do not go any larger in rating. Every 1amp bigger on the fuse allows TEN times the amount of heat/current to the component. If it is blowing there is a reason. Remember the old style fuse boxes at home that you could fit a penny into? Of course you don't. They ALL burned to the ground. Test the battery voltage with the key off, then with the key on, and finally with the scoot running (if you can get it to run)
Post up the voltages, and we can help more.