I have a Toro push lawnmower with a "Ready Start" engine (similar to this one); I just pull the cord and it starts.

I was halfway through mowing the lawn when suddenly a ton of white smoke came billowing out of it. I read that this could be due to the air filter being clogged, so I cleaned it out as best I could. Now, the mower won't start at all, no matter how many times I try.

It has oil, it has gas, the air filter is now cleaned (or at least, cleaner than it was)...what could the issue be? I've had the mower for three years and this is the first time I've ever had it not start.

UPDATE: I tried it again later and got it to start. But here's what it does: it'll run for about 5 to 10 minutes with no problem, and then a ton of white smoke will start coming out of it again. If I turn it off, wait a minute, and start it back up, the smoke will clear up. Then it'll run for another 5 to 10 minutes before doing the same thing again.

From the comments here, it sounds like oil is getting in, but why would it happen on and off like that?

Regardless, I think I'll take it in for servicing since it probably needed it at this point anyway.

  • That sounds like oil got up into the carb. Did you lay the lawn mower on its side before starting it?
    – Evil Elf
    Jul 31, 2013 at 20:36

2 Answers 2


This is probably a better question for the folks on the stack motor vehicle maintenance site. But, if you're mowing along and suddenly a ton of white smoke comes out, it seems like something inside broke and let oil into the combustion chamber. I'd pull out the spark plug and see if there is evidence of oil burning. If so, maybe it ran too hot and broke a piston ring. Briggs engines aren't what they used to be. I've had to rebuild a few of them.

If the air filter was clogged, you'd have black smoke, if any smoke. Most likely, it would just not run before emitting clouds of black smoke.

  • That's interesting. Definitely seems like it's oil getting in, then. (I wasn't aware there was motor vehicle maintenance site – thanks!)
    – daGUY
    Aug 1, 2013 at 13:35
  • @daGUY Yes mechanics.stackexchange.com I signed up, but there are so many guys anxious to answer questions that I never bother to go look anymore. If you post this question there, you should get a lot of replies.
    – Randy
    Aug 2, 2013 at 6:03
  • You were right: I took the mower in for service and the issue was that oil was getting into the chamber. I'm not sure if something actually broke or if I had somehow managed to overfill it without realizing it. Regardless, it was in need of service anyway, so they replaced everything (new spark plug, new air filter, new blade) and now it runs perfectly.
    – daGUY
    Aug 14, 2013 at 13:19
  • @daGUY Glad you have it fixed and thanks for the feedback!
    – Randy
    Aug 14, 2013 at 21:03

Have you tried replacing the spark plug? Also make sure to double check your manual to make sure your air filter is not meant to be soaked in oil.

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