20 Most Recent Briggs & Stratton Lawn-Boy Insight Series 21-Inch 190cc 650 Series Gas Powered Engine Variable Speed Self-Propelled Lawn Mower - Page 4 Questions & Answers

The smoke could be caused by blowby around the piston rings. Pour a small amount of transmission fluid in the spark plug hole and turn the engine over several times. Check the plug for fouling. Also check the coil wire for spark.

B/S webpages show that they recommend a Synthetic 5w-30 oil for their small motors...
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There should be a drain plug on the underside of the mower deck. Raise that side of deck, remove the plug and drain the oil. Replace the plug and add new oil. Hope this helped.

Take carburetor apart and take a can of carb cleaner and spray through all the holes and ports. Take a little wire if you have one and poke through all the holes that you can find. You will probably want to get a carb kit for it while you have it apart. Just make the inside look shiny. They have a youtube video on how to do it. Here's the link http://www.youtube.com/watch?v=seUkziZ2ikk. Here's the Briggs part number for the carb kit 498260.

I don't have this kind of mower. But I was faced with the same problem recently. I got my belt back on by taking a large wrench and affixing it to the bolt head holding the pulley which you want to slip the belt on. Hold the belt firmly against the pulley and turn the wrench and the belt in the grove will walk around the pulley until it slips in place.

Hi,
It's possible that you have condensation built up in your carburator. Tiny droplets can deny gas to the cylinders. Since you put in new gas and I assume you are getting spark, drop the bowl on the carburator and check for this culprit. Could be a quick fix.
Hope this helps... Good luck!

There a plug on right side of engine close to bottom. Remove itto drain old oil.