I have a self propelled lawn mower that has trouble running. It takes about ten pulls to get it started. On the first pull it starts and runs for 5 seconds and then quits. Runs rough when it stays running.. Any tips? Does the carb need rebuilt?

My experience, (have worked on my own and others doing minor maintence, repairs for a major retailer) is to do the cheap stuff first and on an annual basis, 1) change the spark plug at least annually- very easy to do and it keeps your pull rope, other parts from wearing out so quickly by so many attempts to start the mower 2) change the air filter 3) make sure the oil is fairly clean (so your mower will last - check your blade, if it worn out and your can easily tell by looking or if it's bent it will cause the mower to run rough. As to the issue of the mower running for a few seconds then cutting off, check to see if you might have wate or condensation in your gas tank, never leave your mower exposed to the elements, i.e. in the cool of the morning sitting and then the sun warms and causes water condensation inside the tank, drain the tank completely and start with fresh gas, if stored for long periods, either run all the gas out beforehand or use an additive to prevent the gas from turning 'gummy", this will cause major problems.

Correct... a clogged filter will cause it to act like its being choked.. old plug will not fire like it was when new.. and old untreated gas will cause hard starting...