How to Build a Briggs and Stratton Engine

Updated April 17, 2017

Briggs and Stratton engines are found on a large number of garden tools. Lawnmowers, wood chippers and chainsaws are mainstays for Briggs and Stratton engines and can run for years maintenance-free. However, due to the long lifespan of these motors, it is sometimes necessary and less expensive to rebuild the engine than it is to simply buy a new piece of machinery. Briggs and Stratton motors are relatively easy to rebuild and this article will show you how in as few as three steps.

Use the pliers to disconnect the electrical connections on the motor and remove the spark plugs with the ratchet set. For the most part the motor can be rebuilt sitting in its current frame, so there is no need to remove it from its machinery unless you want to. If so, remove it now by loosening the motor mounts and anything attached to the PTO and pulling the motor out of the engine seat. Mount it securely to a work bench.

Drain the oil and remove the engine housing bolts from the top of the engine. Pull the housing and head off of the engine, exposing the camshaft and pistons. Remove the camshaft plugs and pull the camshaft out of the engine (the pistons will come with it). The rebuild kit should come with new pistons and rings. Remove the old pistons by driving out the piston rods and install the new pistons by reversing the process. Install the rings on the new pistons by using the pliers to slip the rings into the shallow slots that encircle the top of the pistons.

Remove all of the old gaskets inside the engine (housing, internal and oil plug). Replace them with the corresponding gaskets from your rebuild kit and then reinstall the camshaft and piston rods. Install the pistons and slide the head back over the pistons and down onto the engine housing. Reinstall the top housing, install new spark plugs, put oil in the engine, reinstall the carburettor and then start it up to do a test run.


If possible try to rebuild the engine on the machinery it is running as this will make the rebuild faster and get you up and running quicker.


Do not overtighten the bolts on any part of the engine. Keep the manufacturer's manual handy and refer to it often for specs.

Things You'll Need

  • Rebuild kit
  • Ratchet set
  • Crescent wrench set
  • Pliers
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