Can someone please tell me why a 3 month old lawnmower won't run? It ran perfectly up until today. I mean, there was no hint of a problem until I tried to use it today. Now, it starts up rather vigorously, but then struggles for a moment and then stalls. It stalls especially quickly if I try to set it down on some grass (and likewise, if I leave it tipped up, it'll run longer, but not much). It has gas and it has oil. I saw the gas cap tip in some other threads and will give that a try, but can those things become plugged after only a partial season of use? And I store it in a garage if that helps. Also, the gas in it is fresh (i.e. wasn't from an old can or anything. In fact the can is new as well - bought it just for this lawn mower). Thanks in advance.

So you tried it with the gas cap removed and there was no improvement, right?

I haven't had a chance to, yet. ;-) My "mow" time was yesterday. It may have to wait until this weekend.

Air filter. Temporarily run without one.

We will wait for your test this weekend. Try both, no cap and no filler but just for a test do not leave it that way.

I was able to get someone to take a look at it and they found nothing wrong. So, verdict: I was probably flooding it. After some instruction in how to not prime it too much (hehe) and how to do a little basic maintenance, I'm back to mowing.

<-- not especially mechanically inclined. I'm not a *complete* idiot, though. The thing ran fine all summer with me pushing the bulb 4 times (despite the instructions saying 3). I pushed it 4 times because I found it always started on the second or third pull after 4 primes, but it would take *at least* 3 pulls or more if I only primed it 3 times. Well I guess I will just have to live with pulling the cord a bit more, hehe. I was shown how to clean the air filter so now I'm thinking that maybe that was what changed (i.e. it's a bit dirty now after most of a season's worth of use, so perhaps that's why it can no longer handle 4 squirts). I'll clean it all up at the end of the season and hopefully it will be a happy mower next year.

Remember to run out the gas or add sta-bil fuel stabiliazer in it for winter storage

Yup, will do.