Toro turf sweeper 4800 HL won't fire, new coil part no. 166-0820 put on

Check to see if you have injector pulse using a noid light.

Coil packs do not have firing orders, engines do. I suspect you were given the incorrect part.

1. Check Fuses
2. Check Ground wire from batt to frame.
3. Check wires on the starter.

unplug the wires going to the coil if still no spark replace the coil

check and make sure its getting fuel. when trying to start, spray some engine starting fluid in spark plug hole. just a little bit. replace the plug then try to start it. if it starts then quits then its a fuel problem. fuel not reaching engine. good-day !

Have you check the fuel pump

buy a new battery. or first go get it checked for free at autozone or oreillys...

Does the mower die right away (cuts out) or does it sputter to a halt. Sputtering out would indicate a fuel problem. If it just cuts out when hot, then more likely an ignition problem. Your coil may need replacing. Take a close look at the coil wire (spark plug wire) and its routing. Make sure it's not touching part of the engine where it's heating up and has caused a "leak" to ground it out when it gets hot. If all is well then check your spark when the engine is hot and cuts out. Make sure you have a very good blue spark and not a weak one (check it cold first and then compare!). Again, indicating a possible ignition coil problem. Hope this helps and best of luck to you.
James

go here https://lookup3.toro.com/request/request.cfm they have a link where you can print your own owners manual for free....good luck

Check the gas and gas tank, you might have water in the gas.