Well, TWO of them actually.
One is a self propelled Craftsman push mower made around 2000ish, and the other is a John Deere self propelled push mower made around 2010 IIRC. Both have had recent tune-ups, and both have nearly identical Briggs & Stratton 6.75hp engines. Both are having the exact same symptoms: they won't fucking start.
The John Deere ran fine, but I noticed it's been getting harder to start the last few times I've used it. It took several hard pulls last time to get it to eventually fire up, but it still ran perfect once it came to life. Now it won't start at all. It seems to come close, then falls on it's face.
The Craftsman is new to me, it started right up and ran great, then died 5 minutes into the mow. It literally lasted 5 fucking minutes the first time I tried to use the damn thing. Same deal as the other one, it tries to start but won't fire up.
I've checked them both thoroughly. Clean air filters, clean carbs, primers seem to work fine, the brackets on the start cables seem to be engaging properly, the pull cables feel normal. Both have good looking spark plugs. There doesn't appear to be any gaskets or O-rings missing anywhere.
When I was taking apart the JD, I noticed the air filter housing had TWO gaskets on it for some reason, and one of them was really crusty. So I ordered two new gaskets thinking that might be the problem. While I was waiting on those to come in, I figured I would buy another cheap mower in the meantime and sell one of them once I fixed the JD. Well LOL, fuck me, so much for that.
I cleaned the carb on the Craftsman and replaced the spark plug, just for the hell of it. Didn't help. I dumped fuel into the carb, still wouldn't start. I'm at a loss for words here.
In summary, don't buy used fucking mowers. Lesson learned. But what's done is done, and at this point I just need to get one of these shitboxes running. Any ideas?