08 Polaris 500 Ho Runs Great Without Air Filter?

The Polaris Sportsman 500 is a serious trail quad, offering lots of power and good traction. Merely there'southward one issue preventing y'all from riding this aggressive 4×4 – information technology dies when accelerating. You may have tried everything, such as replacing the carb or fifty-fifty the unabridged engine. 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 laissez passer electrical current to the spark plug and ignite the engine. Replacing it with a Polaris CDI box should fix the trouble. If non, check other parts of the quad.

Most people would offset call back the issue relates to the carburetor, which controls fuel and air inbound a motor. However, many have discovered the cause of the problem to be electrical – more than specifically, the CDI box.

Polaris Sportsman 500 Dies When Accelerating

This tin can exist a frustrating issue, especially if you don't know why it happens. Keep reading to larn more than about this problem, and other things you can try if replacing the CDI box doesn't help.

What Is Inside a CDI Box?

A typical Capacitor Discharge Ignition box consists of a small-scale transformer, a triggering circuit, a charging circuit, and the main capacitor. The rectifier found inside the charging excursion stops capacitor-discharge before the moment of ignition. Typically, information technology controls the factory rubber kill switches, timing, the spark, and the rev limiter. Depending on the ATV's make and model, the CDI box configuration tin differ and control other things bated from what was mentioned.

What Are the Symptoms of Bad Polaris CDI Box?

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

A bad CDI won't burn at all since everything goes through the box to burn down the motor.
Ignition leads will shorten if yous spray a canteen of water on them.
Frayed wires or loose spade connectors tin can typically exist remedied with a little pinch and some dielectric grease. If this doesn't modify anything, then consider information technology a symptom.
A cooked battery tin usually exist traced back to a defective rectifier/regulator.
Carboned plugs flood 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 Dispatch

While the following usually cause the Polaris Sportsman 500 to dice when accelerating, these should not always be the starting time set of things to inspect. Still, understanding where these bug come from and how to resolve them will non but save you money on repairs but also valuable time:

one. Stator or Scroll Failures

A bad source coil in the stator causes the CDI to stop running. A DC conversion kit is a good replacement for the stock CDI box as it bypasses the lacking source curlicue. However, symptoms for this cause usually overlap with electric wiring or engine compression problems. The best style to find the culprit is to run tests and single out the probable cause 1 at a time – starting with the compression test, which is the easiest, followed by wiring inspection.

For engine compression, perform an initial exam when the engine is cold. When it dies out a 2nd time, test it immediately again. Compare the two results. If the second is significantly lower than the outset, yous might accept found your problem. If this checks out, inspect wiring harnesses that might contact hot surfaces like the exhaust. Also, bank check if the cylinder head has not been melted or chaffed in whatever way.

2. Carburetor

The carb is normally the offset thing owners suspect as the main cause. Symptoms can get severe to where the carb would merely run with the choke on/off or with carb cleaner sprayed down its throat. Some would often bound into replacing bolts, bushings, and the rubber diaphragm at the first sign of a carb problem. They would often forget about giving it a new carb kit when cleaning it out. The needle and seat alignment are often overlooked besides, which is the only reason for the impeded throttle response of your Polaris Sportsman.

Note that for Polaris 500s with CV carbs, you have 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 accept some testing to get it dialed in.

Similarly, it is crucial for ATVs with Keihin carburetors that you bank check the valve clearances, equally they cause the same symptoms equally those of Sportsman 500s with CV carbs. Audit the secondary air intake port at the venturi – the small non-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 repeat from both directions of the valve clearance.

three. Camshaft & Frazzle Lobe

The exhaust lobe on the cam is decumbent to wear if you lot 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 90% of the time.

If the cam turns out to exist the problem, you will demand to supervene upon the rocker arms. Too, think that this troubleshooting stride is only necessary if both the CDI and carburetor check out. It is likewise best performed past a professional as the timing procedures are meticulously done.

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

ane. Fuel

Insufficient fuel may be a cause of your Polaris Sportsman dying when accelerating. If you doubtable this, refill the gas tank and ensure that you plough the cycle key on at least three times before restarting the engine. Additionally, check that the fuel is not fix to "reserve." While checking the fuel quantity, inspect that in that location are no clogged or damaged fuel vents impeding the period of fluid and that the fuel itself is compatible with your ATV and not watered down. Drain and replace the fuel inside your gas tank if establish to be incorrect.

ii. Restricted Airflow

Limited airflow is another cause of ATV bogs when giving gas. Different the other symptoms, this is easier to pinpoint as the machine revs and idles merely fine when you allow off the gas, or your ATV will be running either as well lean or too rich. Usually, a dingy air filter or carburetor, stuck-on-close choke, plugged main jet, junk-filled float basin, misadjusted valves, or air intake tube blockage is responsible for this restriction. Resolving whatsoever of these causes will vary depending on the year of your Polaris Sportsman 500.

iii. Parts Malfunction

If your ATV bogs downward when applying throttle, you likely take defective spark plug wires, non-working reverse speed limiter, electronic throttle control glitches, and sometimes fifty-fifty a bent rocker arm. A seasoned mechanic tin opt to supervene upon defective 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 tin exist catchy and should not exist confused with other known issues for the quad. Some of these mutual bug include the vehicle not turning over, engine not starting, motorcar backfiring, stalling, misfiring, and the Sportsman overheating. Always refer to your owner'due south transmission for guidance and stride-by-step procedures on troubleshooting specific Polaris ATV issues.

four. Throttle Cable

Carbureted Polaris Sportsman 500 ATVs specifically accept what you call an ETC or Electronic Throttle Command. The 2 metal contacts of this assembly should never bear on. Otherwise, information technology volition crusade the machine to die. If y'all figure out that this is the cause of your quad stalling or dying during acceleration, you lot need a throttle cable adjustment. When adjusting, make sure to route the throttle cable correctly forth the aqueduct found on the side of the gas tank. Bank check that the throttle aqueduct is not kinked or obstructed in any style.

5. Cleanliness

Keeping your quad make clean non only make it last longer, just it also helps with your vehicle'south proper role. In some instances, your Polaris Sportsman 500 dies when accelerating due to dirty spark plugs and debris in the fuel vents or the radiator, not considering these parts are faulty. Regular cleaning of your quad inside and out goes a long way in preserving how your wheeler operates. If certain parts are beyond filthy and cannot be salvaged via cleaning, information technology's time to supersede them.

EFI Loss of Spark

For fuel-injected Sportsman 500s, you need to check the map, crank, or TPS sensor harness wires to see if wiring pulled out from the sensor connectors causes the problem. These tiny sensors are bad at shorting out against the starter or engine case. They also do not demand bare spots to be defective as their soft spots internally make them prone to issues. Y'all should also maintain fuel pressure at 39 psi. If you get lower or erratic pressure readings, then information technology could indicate to a fuel pump problem. These two checks are necessary on pinnacle of troubleshooting that you would commonly practice 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:

Remove the bracket (Torx T25).
Disconnect the following plugs from the old CDI box:
- ii pins plug (pickup coil)
- iii pins plug (source coil)
- Blue/white wire (ignition curlicue)
- Blackness wire (kill switch)
- Brown wire (ground)
Connect the new DC CDI box to their corresponding plugs, as seen in the video.

The Polaris CDI kit is a plug-and-play unit that should connect to the same plugs that disconnect from the stock CDI (except for the orangish wire, the hot switched wire). For DC conversion kits, this orangish wire connects to the Polaris Sportsman 500 battery via a hot wire terminal where the box will draw power from instead of the stator. The hot wire terminals on the '98 model are located on either side of the two open up terminals beside the switch top circuit. Y'all can also crimp the bare finish of the orange wire with a female spade tuner and then you lot can press it into the junction board, tucking it neatly into place.

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

Information technology will piece of work fifty-fifty if your source whorl is defective.
Cold-starting volition be easier.

For a '98 Sportsman, you can mount your replacement CDI box on the crossbar in the engine compartment using a cable necktie. Take note as well that only 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 dispatch tin exist frustrating, peculiarly if you exercise not know why it occurs. The problem usually traces dorsum to the CDI box, making cutting-off throttle response easier to resolve and manage.

If the CDI box doesn't need replacement, verify if y'all have spare parts that y'all can use to replace current ones. Regularly cleaning your carburetor and being on meridian of your scheduled oil modify also do wonders for your quad. With restricted acceleration at bay, you tin can fully savor your Polaris Sportsman 500.