6 Major Problems of Polaris Magnum 425 4×4 with Fixes

Polaris Magnum 425 and its 4×4 problems can be plenty. Generally, engine problems like failing to start, unable to rev up, and RPM ups and downs are seen in this ATV (all-terrain vehicle). Thus, no spark or weak spark and static starter motor are also common in this model.

Generally, air filtration, ignition, and clutch springs must be cleaned and repaired when engines malfunction. The spark problem requires replacing ignition parts, such as spark plugs and an inspection of the starter system fixes the motor problem.

Problems and Solutions at a Glance

96 Polaris Magnum 425 Issues

The engine turns over but does not startAdd fuel, clean the vent system, and repair the ignition system
No revs from the engineRepair ETC, air intake, speed limiter, and exhaust system
Excessive engine RPMsRepair drive and driven clutches
Low engine RPMsRepair drive and driven clutches
Weak or no sparkInspect and service the ignition system
The starter motor stuckInspect and service the starter system,

However, there can be many other underlying causes that are causing such problems. To know more specifically, keep reading this article.

What Are The Problems of Polaris Magnum 425 4×4 And How to Fix Them?

Polaris Magnum 425 Servicing

The problems of a Polaris magnum 425 4×4 usually occur in the following parts:

  • Engine
  • Clutches
  • Transmission Service
  • Ignition System
  • Starter System

Let’s discuss the 6 major problems of this ATV:

1. The Engine Turns Over But Does Not Start

The reasons behind this issue include:

  • Fuel malfunction
  • Filters or fuel lines with dirt
  • Fuel pump damaged
  • Water in the engine
  • Compression below the optimum level
  • Spark plug defect


You have to follow the following procedure to troubleshoot this problem:

  • Fix all the problems related to fuel
  • Clean and service the breathing system
  • Disconnect the fuel line and drain the crankcase
  • Inspect carb needle and seat, head gasket, piston, and cylinder (repair as required)
  • Service ignition system

2. No Revs from The Engine

This problem happens due to the following underlying causes:

  • Spark plug malfunction
  • Breathing obstruction
  • Airbox missing
  • Carburetor problem
  • ETC switches and reverse speed limiter restricting speed
  • Mistimed ignition


In order to fix this problem, you need to take the following measures:

  • Replace the cable
  • Clean or repair the fuel intake system
  • Fix the broken ETC, reverse speed limiter, or exhaust system
  • Readjust the ignition timing
  • Fix the carburetor

3. Excessive Engine RPMs

Usually, drive and driven clutch defects cause this to happen.


To fix this RPM issue, changing and repairing the clutches can be helpful. However, removing the excessive weight from the spring and shift can also fix the problem.

4. Low Engine RPMs

This happens due to:

  • Oily converter sheaves
  • Defective drive and driven clutch spring
  • Excessive load on drive clutch shift


Take these measures to solve this problem:

  • A new clutch spring should be installed in the drive and driven clutches
  • Change the belt and/or adjust the tension on the belt with the correct shift weight kit

5. Weak Or No Spark

Weak or no spark indicates a problem in the ignition system. This happens due to:

  • Spark plug damage
  • Spark plug components damage
  • Faulty CDl module or lead connection isn’t good
  • Improper wiring
  • Engine stop switch, ETC switch, or ignition switch defective
  • Faulty terminal board or connections
  • Ignition defect
  • Worn out Crankshaft
  • Flywheel defect
  • Trigger coil air gap more than .016-.040″ (.4-1.0 mm)


To solve this issue, you need to follow some steps:

  • Replace the spark plug
  • Ensure proper wiring
  • Service terminal board or connectors
  • Replace any faulty component
  • Replace the ignition coil and the CDI module if required

The wiring diagram of  magnum 4×4 can help you with the wiring:

wiring diagram of  magnum 4x4

6. The Starter Motor Stuck

The causes include

  • Battery problems
  • Improper cabling
  • Damaged starter button, ignition switch, starter solenoid, or starter motor
  • Blocked or seized engine


If this is the problem, the fixes are:

  • Install a properly charged and fresh battery
  • Check if the voltage is the same on both sides of the circuit breaker, ignition switch/engine stop switch, and starter button
  • Test if the resistance of the starter solenoid coil is 3.4 ohms
  • Properly install all the cables to factory conditions
  • Replace the starter solenoid
  • If any switch is broken, replace it
  • If the engine is seized, it’s better to service the engine with the help of a good mechanic
  • If the problem persists, the starter must be removed for static testing and inspection

Less Common Problems

Apart from these components, brakes and fuel systems can cause some issues.

However, the percentage is negligible. In case you face any starter noise or chain problems, you can watch this video to get help.


Let’s look few of the frequently asked questions and their answers on this topic:

What kind of oil does a Polaris 425 Magnum use?

Ans. A Polaris 425 Magnum uses Castrol power 1 racing 4T 5W-40 oil in the engine.

What type of Transmission Fluid goes in a Polaris?

Ans. Polaris AGL synthetic gearcase and transmission fluid are ideal for ATVs.

Read More- Polaris Magnum 325 Fuel Line Diagram: Guide With Appropriate Images

Final Thoughts

Polaris Magnum 425 4×4 is an older model of the 4-stroke ATVs. Hence, it’s natural to find problems in different parts of this ATV. Mostly, you’ll only get refurbished or second-hand versions of this ATV. Hence, the engine, transmission, starter, and ignition system will show problems.

However, you can solve these problems mostly through proper maintenance and cleanliness. Besides, it’s very crucial to change the oil if needed. No matter what you do, make sure to take professional help when needed. And this article will be more than handy in guiding you.


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