How to examination a small engine charging arrangement, battery & alternator?

Quick Links:

Common Battery Charging System Bug

  • Hearing a click or groan when starting electrical-start engines
  • Onboard electronics aren't operating properly
  • Battery won't accuse or is draining as well quickly

Note: If you lot use a key to start your backyard mower, snow blower or outdoor ability equipment, the small engine includes an electrical charging arrangement with a bombardment and alternator.

Is Your Backyard Mower or Small Engine Bombardment Dead?

If your lawn mower bombardment won't concur a charge, connect it to the charger. If it isn't fully charged within 8 hours, your battery is dead and yous'll need to replace it.

If your lawn mower battery does accuse fully, the charge should not drain if it is not in apply. Troubleshoot continued issues by using a multimeter (service part number 19602) to see if your bombardment drains power while non in employ. If it holds the charge through testing, you may accept an result with the alternator.

Alert: Improper utilise of the battery and charger can consequence in an explosion and burn take chances. Follow the instructions provided by the bombardment and bombardment charger manufacturers:

  • Always article of clothing safety glasses
  • Service batteries in a well ventilated area away from flames or sparks or other ignition sources
  • Do not tip the battery or remove any vent caps

How to Check Alternator on Your Modest Engine

Alternators power the small engine while it is running, keeping the battery charged by circulating power back through the system.

For the easiest method to check your alternator, simply plough on the headlights to your backyard mower or outdoor power equipment. Then, plow off the engine. If the lights dim, the alternator works. If not, information technology doesn't.

If this isn't an option, follow these instructions on how to test alternators.

Attach a Multi-meter to Your Engine

Connect multi-meter (service part number 19602) to your engine based on your alternator type.

You tin decide this by the color of the wires - either Air conditioning volts or DC amps. These wires extend beneath the blower housing and are continued to the stator. For Briggs & Stratton® engines, y'all can match up the wires and alternator'southward configuration with your Alternator Identification Chart. In one case yous find a lucifer, find the Ac/DC setting in the upper right-hand corner.

If yous need assistance in identifying the fashion of alternator installed on your engine, review the Alternator Specifications (PDF), download your illustrated parts list or contact a Briggs & Stratton dealer or the equipment manufacturer.

Once you take your proper setting identified:

  • Prepare the multi-meter dial to AC VOLTS or DC AMPS.
  • Insert the black multi-meter lead into the tester'south COM receptacle.

    • For Air conditioning VOLTS, connect the other end to basis, such every bit an engine bolt or cylinder fin.
    • For DC AMPS, connect the other terminate to the battery's positive terminal. (Note: The bombardment must be grounded to the equipment frame of the engine block to create a complete circuit).

  • Insert the cherry lead on the multi-meter into the tester's receptacle (labeled AC VOLTS or AMPS).
  • Connect the blood-red lead to the appropriate stator output wire. Encounter illustrations below to see that your multi-meter is properly fastened.

Have the Multi-meter Voltage Reading

  • Start the engine and let it run for several minutes to attain its operating temperature.
  • Using a tachometer (service part number 19598), prepare the engine test speed and check the reading on the multi-meter. Unless specified, all tests should be carried out with the engine running at 3600 RPM.
  • Compare your multi-meter reading against the recommended voltage (amps or volts) listed in the using the Alternator Identification Nautical chart, Alternator Specifications or equipment manual.
  • Plow off the engine and disconnect the tester from your equipment.

If your results do not match the specifications, you will need to replace your alternator stator if it is an Air-conditioning VOLT alternators. For DC Amp alternators, replacing the stator, diode or regulator may be required. Otherwise, please contact a dealer.

Warning: Always read the engine and equipment manual(s) before starting, operating, or servicing your engine or equipment to avoid personal injury or property damage. See an authorized dealer if you lot are unsure of any procedure or have additional questions.

Shop Related Maintenance Parts

Acquire how to properly and safely use, troubleshoot, and maintain your lawn mower, tractor, snow blower and other lawn and garden equipment.

View How-To Articles

Videos

Learn about the latest products past Briggs & Stratton, step-past-step instructions on how to locate your lawn mower engine model number and more!

Browse Videos