If you read a review of Hisun’s line of UTVs, you’ll see that there are quite a few positives and negatives to be considered when on the fence about buying one.
The most popular of these models is the Hisun Sector 750, which many consider to be the best value among Hisun utility vehicles.
Many owners absolutely love their Sector 750, swearing by their durability and even referring to them as beasts.
Combine that with one of the most reasonable price tags in the industry, and you can see why this model makes the list of best UTVs for the money for this year.
But some owners have had the opposite experience, needing to do quite a bit of troubleshooting to keep their unit running right.
There are six common problems that seem to recur in a number of Hisun Sector 750 models:
- Excessive noise and heat from the exhaust
- Engine sputtering or stalling
- Engine overheating
- Gears sticking and grinding
- Clutch issues
- Lack of support and service
This guide will explore the causes of each issue, along with proven troubleshooting tips for each as well.
Excessive Noise & Heat From The Exhaust
The Hisun Sector 750 is Hisun’s loudest, making it hard to hear your passenger when out for a ride unless you’re stopped.
This is due to a combination of engine noise and exhaust noise, and these machines are loud both inside and outside of the cab.
Another issue with the exhaust is that the Sector 750 is known to run a bit rich from the factory, which causes the exhaust pipe/muffler to become extremely hot to the point that it may glow red from heat while riding.
The cut down on the noise in the cab, you can install sound deadening mats under the seating and on the inside of the engine compartment to dampen the noise and echo.
And to stop the machine from running rich which causes the exhaust pipe/muffler to glow red hot, you’ll likely need to have your ECU tuned so that the correct air to fuel ratio is recalculated and applied, which should do the trick.
Engine Sputtering or Stalling
Many owners of the Hisun Sector 750 UTV have run into issues with the engine sputtering or stalling out.
This mostly occurs while the machine is in idle. There are three main triggers for this.
- Seat Belt Safety Feature
- Gummed Up Throttle Body
- Fuel Injector
Causes & Fixes
Seat Belt Safety Feature
The first is the seat belt safety feature. There is a sensor in the seat belts that will not permit the engine to get out of limp mode, where it can only go up to around 6 MPH, unless the driver side seat belt is buckled.
This feature is in place with good intentions, but can be a nuisance to drivers who don’t want to wear a seat belt while casually cruising around their properties or doing stop-and-go work tasks.
If you are one of these drivers who does not want to buckle up, the only real way around this is to leave the seat belt buckled behind you at all times.
Some have even rigged it to wrap behind their seat and stay buckled so that it’s out of the way.
You may not want to push the Hisun Sector 750 to its top speed without your seatbelt buckled, but the workarounds above may make sense if driving casually.
Gummed Up Throttle Body
This issue is not quite as simple to fix as the one above, but is the most likely cause of sputtering or stalling while your machine is at idle.
Your throttle body can become gummed up by a buildup of black soot, dirt, and sludge over time.
This buildup will negatively affect engine performance and routinely causes idling issues.
In this case, the throttle body and its parts will need to be thoroughly cleaned following the steps below.
- Remove the throttle body from your UTV.
- Spray it down using a can of WD-40 Carb & Throttle Body Cleaner and scrub down the outer and inner portions using a toothbrush or scrub pad.
- Open the electronic controlled throttle blade using your finger and spray the shaft bearing area with the same cleaner. Make sure to open it back and forth while cleaning to ensure you get it all.
- Test it before reinstalling by hooking up all electrical connections to the throttle body. Turn the key to the “on” position and ensure the throttle blade opens slightly. You should be good to go if so, and can reinstall the throttle body.
Another source of sputtering and stalling is a faulty fuel injector, which is one of the most commonly experienced issues with the Hisun Sector 750.
The fuel injectors on these machines tend to go bad fairly often for a number of reasons.
First, there is no inline fuel filter installed on many Hisun machines, only a screen.
As a result, dirt and debris have a much easier time coming straight from your fuel tank and clogging up your fuel injector, resulting in a number of clogged and faulty injectors.
To combat this, many owners have installed an aftermarket inline fuel filter in their gas line, which minimizes the amount of debris making its way into the fuel injector.
Secondly, the Hisun factory fuel injectors are not known for being well-built. Many owners have resorted to purchasing a superior aftermarket fuel injector online and seeing better results.
To determine whether your fuel injector is the issue, you’ll need to remove the seats and console to expose your engine bay in order to inspect it.
Locate your fuel injector and pull the injector out. Turn the key switch to your machine on and inspect the spray pattern of your fuel injector.
A properly functioning fuel injector will spray out a fine mist, while a faulty injector will spray out streams of fuel.
If the latter is the case with yours, it is either plugged or blown and should be replaced.
Overheating issues seem to be a frequent problem in all Hisun UTV models. This overheating occurs for a few different reasons.
- Fan Switch
- Airlock in Coolant System
- Blown Head Gasket
A flaw with Hisun Sector 750 engines is they are factory-set for the temperature sensor on the radiator not to trigger the fan switch until reaching higher temperatures of around 220 degrees.
The engines aren’t capable of withstanding temps much higher than this, so they’ll overheat before the temperature sensor triggers the fan in time to keep the temps below 220 degrees.
To help prevent this, some owners have resorted to bypassing the need for the temperature sensor to automatically engage the fan switch.
Some have wired a toggle switch to their dash, which bypasses the temperature sensor and gives them the ability to flip on the fan as needed via this switch.
Others have gone as far as wiring their Sector 750 so the fan automatically engages and runs constantly any time the engine is on.
Both methods have reportedly worked well to minimize these overheating issues in Hisun Sector 750 engines.
Air Blockage In Coolant System
An air pocket blockage in the coolant system is another main cause of overheating in Hisun Sector 750s.
When the engine overheats, air can enter into the system. This air usually finds its way to the water pump.
The water pump is unable to pump air, which results in it having a hard time pumping enough coolant as well.
This can result in the radiator staying cool and the engine ultimately overheating.
If you end up with an air pocket in your coolant system, the engine of the Sector 750 will overheat continuously until the air is bled out.
The issue can be tough to diagnose, but it is recommended that if you are experiencing overheating with your Hisun UTV that you follow the process below for bleeding the air from your system to be sure.
- Raise the front end of your UTV about a foot higher than the back end
- Don’t start this process until the engine is cool
- Remove any bleeder bolt from radiator fill cap area
- Remove radiator cap
- Fill it until coolant comes out of the bleeder
- Reinstall the bleeder bolt
- Continue filling radiator until it overflows
- Repeat the steps above for any overflow reservoir too
- Start the engine and let it idle until you see bubbles
- When the bubbles stop, kill the engine and replenish the coolant if needed
- Repeat the process until you see no more bubbling
- Reinstall your radiator and reservoir caps
When you no longer see any bubbles, the air should be bled from your system. If the bubbles won’t seem to subside, you’re likely dealing with a blown gasket.
Blown Head Gasket
When the engine overheats, the head gaskets are prone to blowing. A blown head gasket will then result in constant overheating until replaced.
You can use a head gasket test kit to confirm this, or replace the head gasket if you suspect it’s blown.
Gear Shift Issues
Another common issue with the Sector 750 is to hear a grinding noise when you attempt to shift using the gear shift.
The gear shift may also stick and require a good bit of force to complete a shift.
If you run into this issue in your Sector 750, you can be pretty sure it’s the result of one or both of the locking nuts that hold your shift linkage in place vibrating loose.
When these nuts vibrate loose, your shift linkage can move to a wrong position, which will cause the gear shift to stick and the grinding noise.
To fix this, you’ll need to readjust the shift linkage back into its correct position.
You can do this by removing both seats and the center console to expose the engine bay, then locate the shift linkage on the passenger side.
Hold the shift linkage turnbuckle in place using an 8mm wrench while at the same time loosening the locking nuts on both ends using a 14mm wrench (assuming they’re not both loose already).
Then rotate the shift linkage counter clockwise so that it shifts left or right, depending upon which locking nut is loose and which way it has transferred.
You can usually tell when its in the correct position by looking at the gear lights on the dash.
When you’ve gotten it back into the correct position, tighten your locking nuts to hold it there and reinstall the center console and seats.
If this doesn’t do the trick, you’ll need to continue adjusting the shift linkage until its in a position where you experience no more sticking or grinding noise.
The Hisun Sector 750 makes use of a wet clutch that is lubricated and cooled with engine oil.
This clutch is ideal for prolonging the life of the transmission, but is prone to being damaged and causing problems.
You can be pretty sure you have a wet clutch issue if when you initially accelerate, your UTV moves slower than it should until it eventually catches (the belt – you’ll feel it) and accelerates as it should.
This is your clutch slipping and is likely due to worn out clutch shoes, and can happen in High gear as well.
If this happens, you’ll likely need to either replace the clutch shoes or the entire clutch system, and you’ll likely need to see your dealer.
There are two main causes of your wet clutch failing.
If you often drive your Sector 750 in High gear at low speeds, or haul heavy loads in High gear, you’ll damage the clutch and wear it down over time.
Be aware of which gear you’re driving in depending upon the type of driving you’re doing to prevent this.
It’s also essential to use an oil approved for wet clutches rather than just your typical motor oil.
Be sure that the oil you use is labeled “JASO”, but most oil made specific for UTVS or ATVs should work just fine.
Lack of Support and Service
Although Hisun has a support center in Texas, one of the more common issues owners run into is a lack of assistance with troubleshooting many of the problems we’ve covered.
To complicate matters further, it can be tough to find a service center or mechanic who is familiar with and willing to work on Hisun machines depending upon your location.
With that in mind, Hisun Sector 750 owners find themselves needing to be rather self-reliant when it comes to diagnosing and repairing issues with their machines.
Though it seems that some Hisun Sector 750 owners are willing to live with some of these issues in exchange for a lower price point and added features, many of the common problems experienced can be avoided by adhering to the suggested maintenance schedule and being proactive in caring for their vehicles.
Yet still, others are completely out of their control.
If considering purchasing a Hisun Sector 750, it’s important to keep in mind that they do offer much of the same ability as some of their more expensive counterparts in the UTV market.
But it’s equally important to consider your willingness and ability to troubleshoot issues on your own should they arise with these machines.