Predator 3500 Generator Won’t Start (Solved)

Why won’t your ‘Predator 3500’ generator start? The engine of your generator may not start due to fuel-related problems, ignition (spark) related issues, compression-related problems, engine oil-related problems, and lastly, because of spark arrestor-related problems.

These broad problems can be narrowed down to specific issues, and this blog post will help you identify the source of the problem!

Key Takeaways

  • Clogged Carburetor – If you leave the Generator unused for a long period with a fuel (which contains high % Ethanol), then the holes in the carb can get blocked. This is the most common reason for a ‘No start’ condition. Clean your carburetor.
  • Fuel Passage blocked & clogged fuel filter
  • Clogged Spark Arrestor
  • Low/No Compression – If the compression is low, the most likely fix is to adjust the valves.

What Is the Correct Way To Start a Predator 3500 Generator?

(Skip past this section if this isn’t the first time you’re using a Generator!)

Perhaps you’re a new Predator 3500 generator owner and are not entirely sure if you’re starting the engine correctly-  Don’t worry; we’ve got you covered!

Many prefer an ‘Electric Start’ to their generator because of the ease but being aware of how to start your generator manually is also essential- therefore, we’ve got a thorough guide for both.

How To Start a Predator 3500 Generator Manually?

  1. Disconnect all devices and loads from the Predator 3500 generator.
  2. Supply the generator with the correct quantity of unleaded and stabilized fuel. 
  3. Rotate the ‘ESC Throttle’ or ‘Economy ‘Switch’ button to the ‘Off’ position.
  4. Rotate the ‘Combination Start’ button to the ‘Start’ position.
  5. Grab the ‘Starter Handle’ of the engine lightly and gently pull it back a few times to let gasoline flow into the carburetor.
  6. Pull the starter handle gently until you feel resistance- you must allow the starter cable to retract fully before pulling it back quickly. Repeat this process until the Predator 3500 generator fires up.
  7. Ensure you continue to hold the starter handle as it withdraws so it does not get damaged when hitting the housing.
  8. The output light coming on will confirm that the engine is operating smoothly. Allow the engine to run for several seconds before rotating the ‘Combination Switch’ back into the ‘Run’ position. Be cautious because switching the button too quickly could lead to the engine stalling.
  9. Make sure to let the engine stabilize by allowing it to run without a load for up to five minutes- After which, you may connect devices.

How To Start a Predator 3500 Generator Electrically?

  1. Disconnect all load devices from the generator.
  2. Turn the ‘ESC Throttle switch to the ‘Off position.
  3. Rotate the combination switch to the ‘Start’ position.
  4. Push and hold the ‘Starter Engine Button’ for three seconds. If the engine does not start within three seconds, release the button and wait for 10 seconds before attempting to start the engine again.
  5. Once the engine starts and the output light switches on, wait several seconds before twisting the combination button to the ‘Run’ position. However, do not rotate it too quickly because the engine could stall.
  6. Ensure the engine runs for five minutes without load so that it may stabilize.

NOTE: If a warm engine will not start- turn the combination switch to the ‘Run’ position before reattempting to start the engine. This applies to both a manual and an electric start.

Most Common Problems Preventing Predator 3500 Generator From Starting

Generally, there are four main issues in a ‘Predator 3500’ generator that prevents it from starting. 

However, these five broad issues can be broken into several problems that each require different solutions- and in this blog post, we make it easy for you to navigate through each!

1. Fuel-Related Problems Preventing Predator 3500 From Starting

We’ll list out some questions, and if your answer happens to be a ‘yes’ to any one of them, you’ll have to read the solution and fix your generator accordingly.

  • Are you using fuel with high ethanol content (>10%)?
  • Is your fuel valve in the ‘closed’ position?
  • Are you using gasoline with more than a 10% ethanol content?
  • Have you forgotten to turn the choke to the ‘start’ position with a cold engine?

Solution if you answered yes to any of the above questions –

  1. Wipe the fuel cap and the area around it. Then unscrew the fuel cap and remove it.
  2. Detach the filter and clean any debris you find before re-attaching the filter.
  3. Get ahold of the right gasoline- 87+ octane or higher unleaded gasoline treated by a stabilizer such as ‘Sta-bil’ or ‘Seafoam.’ Ensure that you do not use gasoline with more than 10% ethanol content (E10); that includes – E15, E20, or E85 gasoline.
  4. If you have already used ethanol-enriched gasoline, you will have to flush the fuel from the generator and replace any parts that have been affected.
  5. Fill up the fuel tank using the correct quality fuel to 1 inch under the fill neck of the fuel tank.
  6. Secure the fuel cap to the generator and turn the fuel valve to the ‘Open’ position.
  7. If your engine is cold, rotate the ‘Choke’ to the ‘Start’ position before attempting to power up the generator.
  • Did you forget to prime your carburetor?

Solution –

Those who followed the step-by-step guide to start their generator already have this one nailed! 

To prime your carburetor, grab the starter handle and gently pull it a few times to allow the fuel to flow into the carburetor.

  • Is the fuel passageway dirty?
  • Is the fuel filter clogged?

Solution –

Clean out the passageways of your generator using a fuel additive. Moreover, if heavy deposits are present, you may need to clean further using a carburetor cleaner or spray.

Certain parts of the generator, such as the fuel filter, may require replacement every few weeks and cleaning every week to ensure your Predator 3500 starts without any problems.

  • Is the carburetor needle stuck?
  • Can you smell fuel in the air?
  • Is there too much fuel in the chamber?

Solution –

If your carburetor needle is stuck, you only need a tap of effort to solve it! (Literally). Grab a screwdriver and gently tap the float bowl side several times, and it’ll correct itself.

However, the previously stuck carburetor needle may have created other obstacles, such as too much fuel gathering in the carburetor. 

Follow the below-mentioned steps to resolve it-

  1. Rotate the choke to the ‘Run’ position.
  2. Remove the spark plug.
  3. Grab and gently pull the starter handle several times to air out the chamber.
  4. Reattach the spark plug.
  5. Rotate the choke to the ‘Start’ position.

2. Engine-Oil Related Problems Preventing Predator 3500 From Starting

If your Predator 3500 is balanced on a slope, it will cause the generator to face an oil shortage; therefore, ensure that your Predator 3500 is placed on a uniform platform.

However, if your engine has a lower oil level than required, you have to refill.

  1. Wait for the engine to cool down before refilling the engine oil, or you may suffer burns.
  2. Unscrew the bolt on the left side of the generator panel  and remove the ‘Oil Fill Access Door.’
  3. Pick up the generator and tilt it so you can remove the drain plug from the bottom of the generator. Afterward, place the generator back on the ground.
  4. Wipe down the ‘Oil Fill Cap’ and the area around it before twisting it counterclockwise and removing it.
  5. Set down an oil drain pan directly under the drain plug opening.
  6. Detach the ‘Oil Drain Bolt’ and tilt the generator around until you are sure all the engine oil has escaped through the drain plug.
  7. Pick up and tilt the generator to reattach the drain plug before setting it back down.
  8. Reattach the ‘Oil Drain Bolt.’
  9. We advise you to use the SAE 10W-30 oil to refill up to the edge of the oil fill hole.
  10. Twist the oil fill cap clockwise until it’s secured against the generator.
  11. Refasten the oil fill door.

3. Compression-Related Problems Preventing Predator 3500 From Starting

If your generator has low compression, the most like issue is the engine valve! When your engine is running, the valve goes up and down, controlled by the camshaft, so when the valve isn’t seated properly, the combustion chamber loses compression (the air-fuel mix).

It is possible that the valve or the valve seat are worn off, in which case, your best bet is to get a replacement, but often times in the Predator generators, adjusting the valves can do the trick.

Other than an unadjusted valve, the ‘no/low compression’ situation may also be caused due to loosely attached or broken spark plug, cylinder head, head gasket, or poor lubrication.


Tighten the spark plug, cylinder head, and head gasket. Ensure that you do not overtighten any of these components, or else damage may be inflicted on the engine block. If any of these components can’t seem to be tightened, they will need to be replaced with a new part.

4. Spark Arrestor Problems Preventing Predator 3500 From Starting

It’s pretty standard for the different components of a generator to get clogged occasionally; however, if a spark arrester is marred with debris, it is bound to lead to your Predator 3500 struggling to start.

How To Clean the Spark Arrestor of Predator 3500?

  1. Unscrew the six bolts at the back of the generator and remove the grate.
  2. Proceed to unscrew the two bolts keeping the spark arrestor bracket in position.
  3. Get ahold of a wire brush and clean out the soot from the spark arrestor. However, if the spark arrestor seems to be damaged, replace it.
  4. Reattach the spark arrestor bracket and grate.
  1. Spark Plug and Ignition Problems Preventing Predator 3500 From Starting

Various spark arrestor problems may occur and prevent the ‘Predator 3500’ from starting:

  • The spark plug cap may be loosely attached.
  • The spark plug electrode may be wet or dirty.
  • The spark plug gap may be imperfect.
  • The spark plug gap may be broken.
  • Incorrect spark timing or ignition issues.

If you suspect any of the above spark plug-related issues are preventing your Predator 3500 from starting, we highly suggest you hop onto this (add hyperlink) blog post as it addresses all these issues in-depth.


As you may have realized- if you’re ‘Predator 3500’ is not starting, you must not be alarmed. Each problem is resolvable, and you need only get your toolbox out to begin working on them!

But we understand – everyone’s situation is unique. It’s possible you might not have found your solution above. Please let us know your exact situation down below and we will try to help. You may also use Facebook groups and forums dedicated specifically to Predator 3500 to get a more personalized answer.

6 thoughts on “Predator 3500 Generator Won’t Start (Solved)”

  1. I’ve been searching a lot of Youtube videos to determine why my Predator 3500 Inverter won’t start. Due to medical problems, it was left unattended for about 6 months. I have only run it 3-4 times since purchase. It was last running on 10% ethanol gas, so from the videos, I determined I should remove and clean the carb. By the way, the battery was dead and wouldn’t take a charge, so I replaced it. Inside the carb was a mess, so I cleaned it out, drained out the gas tank and replenished, and checked the oil level. I also replaced the spark plug. With a fresh battery, new gas and plenty of oil, it still won’t fire. I used a spark plug adapter between cap and plug, and am getting spark. Not sure what to do next. Any help is appreciated.
    Lincoln Z

    • Might be compression issue (leak inside the cylinder)! Or maybe the valves are not opening/closing at the right time. Best thing will be to take it to a professional.

  2. My predator will turn over but not start change the carb and it ran fine for week and then just shut off then change the coil and the spark plug and now it wants to start but won’t what could be the issue thanks

  3. Predertor generator works fine when pull start,but with the battery it sounds like it’s spinning but not engaging


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