The Polaris Sportsman 500 is a serious trail quad, offering lots of power and skillful traction. But in that location'south one issue preventing yous from riding this aggressive iv×4 – it dies when accelerating. You may take tried everything, such every bit replacing the carb or even the entire engine. And so, you may be wondering why your Polaris Sportsman 500 dies when accelerating.

The reason the Polaris Sportsman 500 dies when accelerating frequently comes from the CDI box, which is used to pass electrical current to the spark plug and ignite the engine. Replacing it with a Polaris CDI box should fix the trouble. If not, check other parts of the quad.

Most people would first call back the event relates to the carburetor, which controls fuel and air entering a motor. Nevertheless, many accept discovered the crusade of the trouble to be electrical – more specifically, the CDI box.

Yellow ATV Driving on a Trail

Polaris Sportsman 500 Dies When Accelerating

This can be a frustrating upshot, especially if you don't know why it happens. Go along reading to learn more than about this problem, and other things you can try if replacing the CDI box doesn't assist.

What Is Inside a CDI Box?

A typical Capacitor Discharge Ignition box consists of a pocket-size transformer, a triggering circuit, a charging circuit, and the principal capacitor. The rectifier establish within the charging circuit stops capacitor-belch before the moment of ignition.

Typically, it controls the factory safety kill switches, timing, the spark, and the rev limiter. Depending on the ATV's make and model, the CDI box configuration can differ and command other things bated from what was mentioned.

What Are the Symptoms of Bad Polaris CDI Box?

When a Polaris Sportsman 500 idles but dies, information technology tin can point to different things, such as misfires, starting problems, rough running, and even a stalling motor. The below signs tin can help you lot determine if the problem is from the CDI box:

  • A bad CDI won't fire at all since everything goes through the box to fire the motor.
  • Ignition leads volition shorten if you spray a canteen of h2o on them.
  • Frayed wires or loose spade connectors can typically be remedied with a little pinch and some dielectric grease. If this doesn't change anything, and then consider information technology a symptom.
  • A cooked bombardment can usually be traced back to a defective rectifier/regulator.
  • Carboned plugs overflowing the carburetor and point towards a faulty CDI box.
  • Testing your ignition coils with a multimeter gives results outside of the secondary resistance parameters indicated in your manufacturer specifications.

Causes of Restricted Acceleration

While the following usually cause the Polaris Sportsman 500 to dice when accelerating, these should non ever be the start set of things to inspect. Still, understanding where these problems come up from and how to resolve them will not only salve you coin on repairs just also valuable time:

1. Stator or Whorl Failures

A bad source coil in the stator causes the CDI to stop running. A DC conversion kit is a skilful replacement for the stock CDI box equally it bypasses the defective source curlicue. Still, symptoms for this cause normally overlap with electrical wiring or engine compression bug. The all-time way to observe the culprit is to run tests and unmarried out the likely cause one at a time – starting with the compression examination, which is the easiest, followed by wiring inspection.

For engine compression, perform an initial test when the engine is cold. When it dies out a 2d time, test it immediately again. Compare the 2 results. If the 2d is significantly lower than the starting time, you might take found your trouble. If this checks out, inspect wiring harnesses that might contact hot surfaces like the frazzle. Also, cheque if the cylinder head has not been melted or chaffed in any mode.

ii. Carburetor

The carb is usually the first thing owners suspect as the primary cause. Symptoms tin get severe to where the carb would just run with the choke on/off or with carb cleaner sprayed downwards its throat. Some would frequently spring into replacing bolts, bushings, and the safe diaphragm at the first sign of a carb trouble. They would often forget about giving information technology a new carb kit when cleaning it out. The needle and seat alignment are oft overlooked too, which is the only reason for the impeded throttle response of your Polaris Sportsman.

Note that for Polaris 500s with CV carbs, y'all accept to maintain a certain corporeality of vacuum to operate the slide properly. This necessitates running a lid and changing the jets. These carbs are very sensitive to airbox changes. Running a new carb kit and modded airbox may take some testing to go it dialed in.

Similarly, it is crucial for ATVs with Keihin carburetors that you check the valve clearances, as they crusade the same symptoms as those of Sportsman 500s with CV carbs. Inspect the secondary air intake port at the venturi – the small not-replaceable jet embedded in the passageway. Disassemble the carb, spray cleaner through the passage, then take a small-diameter wire and run it through. Blow through with compressed air to complete your thorough cleaning and echo from both directions of the valve clearance.

three. Camshaft & Frazzle Lobe

The exhaust lobe on the cam is prone to clothing if yous neglect scheduled oil changes. In extreme cases, the exhaust lobe is so worn-out that a rebuild is needed. Interestingly, the exhaust lobe wearing out on the camshaft is responsible for the restricted acceleration of the Polaris 500 xc% of the time.

If the cam turns out to exist the trouble, you lot volition need to replace the rocker artillery. Also, recollect that this troubleshooting step is only necessary if both the CDI and carburetor bank check out. It is too all-time performed past a professional person as the timing procedures are meticulously done.

Other Things to Check if Your Polaris Sportsman 500 Dies When Accelerating

1. Fuel

Insufficient fuel may be a crusade of your Polaris Sportsman dying when accelerating. If you suspect this, refill the gas tank and ensure that yous turn the bike cardinal on at to the lowest degree three times earlier restarting the engine. Additionally, bank check that the fuel is not set to "reserve."

While checking the fuel quantity, inspect that in that location are no chock-full or damaged fuel vents impeding the flow of fluid and that the fuel itself is compatible with your ATV and non watered down. Drain and replace the fuel within your gas tank if constitute to be incorrect.

2. Restricted Airflow

Limited airflow is another cause of ATV bogs when giving gas. Unlike the other symptoms, this is easier to pinpoint as the machine revs and idles only fine when y'all let off the gas, or your ATV volition be running either also lean or also rich.

Commonly, a dingy air filter or carburetor, stuck-on-close choke, plugged main jet, junk-filled bladder bowl, misadjusted valves, or air intake tube blockage is responsible for this restriction. Resolving any of these causes will vary depending on the year of your Polaris Sportsman 500.

three. Parts Malfunction

If your ATV bogs downward when applying throttle, you probable have defective spark plug wires, non-working reverse speed limiter, electronic throttle control glitches, and sometimes fifty-fifty a aptitude rocker arm. A seasoned mechanic can opt to supercede lacking parts with OEM ones and resolve the issue themselves. Otherwise, these mechanical failures merit a visit to a Polaris dealer to administer repairs.

Identifying why your Polaris Sportsman 500 dies when accelerating can be tricky and should not exist confused with other known issues for the quad. Some of these common bug include the vehicle non turning over, engine non starting, machine backfiring, stalling, misfiring, and the Sportsman overheating.

Always refer to your owner's transmission for guidance and step-by-pace procedures on troubleshooting specific Polaris ATV issues.

4. Throttle Cable

Carbureted Polaris Sportsman 500 ATVs specifically take what you call an ETC or Electronic Throttle Command. The two metallic contacts of this assembly should never touch. Otherwise, it will cause the machine to die. If you lot effigy out that this is the crusade of your quad stalling or dying during dispatch, you lot demand a throttle cable adjustment.

When adjusting, make sure to route the throttle cablevision correctly forth the channel establish on the side of the gas tank. Check that the throttle channel is non kinked or obstructed in any way.

5. Cleanliness

Keeping your quad clean not merely make it final longer, simply it also helps with your vehicle's proper function. In some instances, your Polaris Sportsman 500 dies when accelerating due to muddied spark plugs and droppings in the fuel vents or the radiator, not because these parts are faulty.

Regular cleaning of your quad within and out goes a long mode in preserving how your wheeler operates. If certain parts are beyond filthy and cannot exist salvaged via cleaning, information technology's time to replace them.

EFI Loss of Spark

For fuel-injected Sportsman 500s, yous demand to cheque the map, creepo, or TPS sensor harness wires to meet if wiring pulled out from the sensor connectors causes the problem. These tiny sensors are bad at shorting out confronting the starter or engine case. They also practice not demand bare spots to be defective equally their soft spots internally make them prone to issues.

You should as well maintain fuel pressure at 39 psi. If you get lower or erratic pressure readings, then it could bespeak to a fuel pump problem. These two checks are necessary on top of troubleshooting that you would normally do for a carbureted Polaris 500.

Polaris CDI Installation

This video demonstrates the proper installation of a Polaris stator and CDI ignition kit for a 1998 Polaris Sportsman 500.

How to install the CDI box:

  1. Remove the bracket (Torx T25).
  2. Disconnect the following plugs from the old CDI box:
    • 2 pins plug (pickup scroll)
    • 3 pins plug (source coil)
    • Blueish/white wire (ignition ringlet)
    • Blackness wire (kill switch)
    • Brown wire (ground)
  3. Connect the new DC CDI box to their respective plugs, as seen in the video.

The Polaris CDI kit is a plug-and-play unit of measurement that should connect to the same plugs that disconnect from the stock CDI (except for the orange wire, the hot switched wire). For DC conversion kits, this orange wire connects to the Polaris Sportsman 500 battery via a hot wire terminal where the box will depict power from instead of the stator.

The hot wire terminals on the '98 model are located on either side of the two open terminals abreast the switch top circuit. You tin can too crimp the blank end of the orange wire with a female spade tuner and so y'all can press it into the junction board, tucking it neatly into identify.

Installing a DC conversion upgrade kit is adequately straightforward. Choosing to upgrade to a DC ignition system is improve than a conventional CDI box that requires a working source coil for two reasons:

  1. It volition piece of work even if your source coil is defective.
  2. Cold-starting will exist easier.

For a '98 Sportsman, you tin mount your replacement CDI box on the crossbar in the engine compartment using a cablevision tie. Take note besides that but an OEM Polaris CDI box replacement resolves the loss of power in certain cases.

Conclusion – Polaris Sportsman 500 Dies When Accelerating

Your Polaris Sportsman 500 dying out during acceleration can be frustrating, especially if you do not know why it occurs. The problem commonly traces back to the CDI box, making cutting-off throttle response easier to resolve and manage.

If the CDI box doesn't need replacement, verify if you accept spare parts that y'all tin use to supersede current ones. Regularly cleaning your carburetor and beingness on top of your scheduled oil change too practice wonders for your quad. With restricted acceleration at bay, y'all tin can fully relish your Polaris Sportsman 500.