How to Build a Generator From a Lawn Mower Engine

If you want to build a generator from a lawn mower engine, it will take lots of time and patience. The two parts you will need, a car alternator and lawn mower, aren’t very compatible.  You will have to find a vertical shaft lawn mower engine, am alternator with a single wire connection and internal regulator. 

Things you will need to build a generator from a lawnmower engine:

• Iron pulley


• A type belt


• Car battery


• Bolts


• Pulley puller


• Socket wrenches, screw drivers, hammer and nails


• Alternator with internal voltage regulator


• Lawnmower engine


• Steel mounting bracket


• 2 x 4s and plywood for a base

1. Get on the lawn mower so you can get to the blade. You will then put it on secure hoist with 2x4s. Next you will take off the blade by removing the mounting bolt. Make sure you brace the blade in order to do this. Take off the coupling that is under the blade.


2. Take the cast iron pulley and attach it to the lawnmower blade. You will have to figure out the size of the pulley that will be used. Think about the right resistance needed to balance the throttle and keeps the motor working steady.


3. Cut and trace a pattern in a piece of steel or plywood to mount the alternator and mower to the base. They should be the right distance from the belt you want to use.  Make sure you get the materials you need together and put the belt on.  You will have to create a diagram to construct this part. 


4. Cut more holes for the bolts that will join the lawn mower and alternator onto the base. All of them have mounting bolts. The lawn mower will have bolts that join the engine to the mower shield. The alternator has bolts that will join it to the engine block.


5. Mount the engine onto the mounting bracket. You will then slide the bolts that were used to mount the engine to the mower shield in the holes on the bracket and plywood. The shaft and pullet should then go through the bracket.


6. Make sure the pulley goes into the plywood by mounting the alternator engine to the bracket face down. You will use the bolts that mount to the engine block or you can change another attachment if the bolts aren’t functioning properly. 


7. Construct the base with 2x4 boards. You will cut them a length longer than the bracket and just as wide. Next you will cut a cross brace and two sides. At this point you can attach them together.


8. Take the belt and attach it to the engine puller and alternator to set the bracket and generator on the base. You will secure it with screws, bolts, and large nails.


9. Check the output of the alternator by joining a simple voltage reader to the alternator. You will then test the internal temperature of the alternator by putting a thermometer in the casing.