Why do I keep blowing fuses?

I have a 150cc 4 stroke engine with electric starter. Once I ride for even 5 minutes, as soon as I turn it off, it will not start again. The fuse blows every time. I tried a stronger amp fuse but still no luck. I may be connecting it wrong (There are 3 wires black to neg on battery, red to pos and the wire with fuse box attached to red as well)? This second wire attached to the red positive side of the batter is the one with the fuse that keeps breaking. It is the only fuse for the whole scooter. There is another wire with a box and 5-6 wires attached that appears to just be for flashers and lights but I am not sure. I am not a mechanic and know very little about wiring and all that. Please help me.

Without a wiring drawing, you (and I) are mostly guessing.

First, try looking at obvious places - terminals and junctions, entry holes to lights, etc. for frayed insulation or bare wires.

When you do have it running, is there one or more itmes that don't work? The horn, one signal light, headlamp, etc? Try tracing that wire back, and/or unhook that device temporarily.

Try unhooking all the other wires from the junction - if they are the quick-disconnect terminals - and start the bike. Then plug them in one at a time until the fuse blows. Then trace that wire looking for a short.