what causes lawn mower to sputter and belch smoke?

just tried to start it up and it took way longer to start up than normal and it started belchin white smoke like crazy could it be the spark plugs or what?

White smoke is indicative of water. If it's been a while since you started it, I'd call it pretty normal.

Pull the plug and see what the electrodes look like.

Take the carburetor top off and clean the filter out.

Bad Gas

Try loosening the Feldspar gasket before starting. If that doesn't work declutch the rear modulator.

My lawn mower belches and smokes too. I think it is normal.

Quote from rayzac : My lawn mower belches and smokes too. I think it is normal.

So you also have succumbed to the "What would the Lounge Guys and Gals think?" Syndrome...

MUAHAHAHAHA

Quote from rayzac : My lawn mower belches and smokes too. I think it is normal.

Did you add too much oil (or the wrong kind)?

I second the clean filter idea. When they get clogged...the lawnmower sputters and smokes. If you could buy a new air filter that would be best...otherwise just clean the filter the best you can. I would also make sure your spark plug is set at the proper specs and clean the spark plug of carbon soot by taking a piece of fine sandpaper and just lightly sand off the buildup. If that doesn't work...could be poor gas. Not sure how old the gas is...but higher octane may help. If you have some carb spray...I would use it to clean your carburetor before putting the filter back in. Just some tips.

Quote from kdt : Try loosening the Feldspar gasket before starting. If that doesn't work declutch the rear modulator.

What ever you do, DO NOT TOUCH THE SPACE MODULATOR, you could be disintegrated.

Quote from General Ghoul : What ever you do, DO NOT TOUCH THE SPACE MODULATOR, you could be disintegrated.

OP skip this foolishness - it's definitely a stuck fetzer valve - you need to treat it with some 3 in 1 oil and gauze pads. A good 10 quarts of Quaker State antifreeze can't hurt either.

Also clean your air filter on it.