Starts great, but why will it only run for approx. 5 min then shuts down and wont reignite?

change the oil to the correct specification first. As the engine runs the heat changes the viscosity and overheats or trips the oil alert switch. If its over 10 years old change the oil alet magnetic switch

What is your temperature rise during the 5 minutes it does run? Could be overheating and kicking out on limit switch. Watch the diagnostic light for a code. (3 blinks means this, 4 blinks means that etc.)

Had a similar issue with my dewalt 4200 pw. Unit starting shutting off after spraying for about 5 min. Then difficult to restart, but would start again eventually only to shut down a few min later. Had new engine oil, new pump oil, good gas. I changed the spark plug and unit runs great again!

There is a sensor in the tube that is a safety feture. it is a snap disc it maybe faulty, it is reading that the tube is to hot and shutting down, it cools and works again, check snap disc and also they need pleanty of fresh air.

check float valve level could be sticking or shuting your fuel off also make sure you have good fuel flow from fuel valve

You'll need to determine whether your lacking spark or fuel when no start happens, do you know how to do that?

it sound like you have a bad distributor, good luck.

the engine is getting to hot & shutting down either not the right fuel mix or not enough oil in engine sometimes the mixture screws need to be adjusted

Check your connecting exhaust vent for a blockage.
Remove the vent and run a 45 minute timed dry load and see if it works correctly.
Report back.

I WOULD LOOK FOR AN ELECTRICAL (IGNITION) SHUTDOWN,CHECK WHEN IT SHUTS DOWN WITH SPARK TESTER TO SEE IF IT IS FIRING.