How To Fix a Predator 3500 That Only Runs on Start Mode?

The bestseller Predator 3500 is immensely popular for powering up an RV, campsite, or even your house during electricity crises! However, even this powerhouse may sometimes face difficulties- such as being unable to run unless on ‘start’ mode, otherwise known as ‘choke’ mode, or sometimes they don’t start at all!

In this post, we will try to help you fix the 3500 w generator that only runs on the start mode. Here are the most common reasons why this might be happening –

The float bowl may be clogged due to stale gas; the carburetor’s main jet, emulsion tube, or main jet may be blocked. Furthermore, the carburetor may not be tightly attached to the intake, or its gaskets may be damaged.

Don’t worry- all of the above-outlined issues are resolvable; you only need to read further to discover the ultimate fixes!

1. Float Bowl Is Clogged With Stale Gas

Stale fuel is the root cause of fuel build-up in the carburetor- and it is a common cause of the Predator 3500 working only on choke.

Gasoline has two expiry dates, depending on whether it is stabilized or not, that you must keep in mind.

The expiry date of un-stabilized gasoline is 1 to 3 months, so if you have a 1-month-old or more un-stabilized gasoline fostering within your generator, it must be expired! 

However, if your gasoline has been treated with stabilizers such as ‘SeaFoam’ or ‘Sta-bil,’ it will probably last 12-15 months before expiring. Therefore, always ensure your gas is ethanol-free and stabilized for the best results!

If you’ve done the math and realized that expired gas within your float bowl is causing your Predator 3500 to malfunction, follow the steps below for a remedy!

Note – You would likely prefer to watch a video instead of reading the step-by-step guides – for which you can always search Youtube!

How To Drain Old Gas From Predator 3500 Generator?

  1. Shut off the fuel valve so the carburetor is no longer in sync with the fuel tank.
  2. Remove the side panels of your Predator 3500.
  3. Now identify where the carburetor is- hint: it will have a piece of blue tape.
  4. The carburetor drain pipes will be coming out of either side of the carburetor; peek under the generator to see where they end and place a small gasoline container in that spot (make sure to put it beneath the pipes accurately so that the container catches all of the stale gas).
  5. Now move back to look at the carburetor and identify the ‘carburetor drain screw,’ pro-tip: it will look like a regular screw.
  6. Use a screwdriver and twist the screw counterclockwise a couple of times until an ounce or so of gasoline has come out from the drain pipes.
  7. After a few moments, you may proceed to tighten the screw in a clockwise direction.
  8. Lastly, proceed to open the fuel valve.

2. The Carburetor’s Main Jet, Emulsion Tube, or Pilot Jet Is Clogged

Your generator requires the perfect amount of fuel to operate, and the ‘main’ and ‘pilot’ jet carry out essential functions of fuel distribution. 

Therefore, if the ‘main’ or ‘pilot’ jet is compromised, you can expect your Predator 3500 to only operate while on ‘start’ mode.

Cleaning out the jets requires some dismantling, so be sure to follow the steps accurately.

How To Clean Out Predator 3500’s Main Jet and Emulsion Tube?

  1. Use a 10mm wrench to unscrew two to three screws holding the airbox in place next to the carburetor. You may need an extension for one of the screws at the back so keep one handy!
  2. Turn off the fuel valve, then gently tug the carburetor towards the right side until it comes off the generator.
  3. There will be a plug holding on to the carburetor, so reach in and disconnect it so the carburetor comes entirely out.
  4. Unscrew the 10mm bolt at the bottom of the carburetor to remove the outer covering of the carburetor.
  5. There will be a narrow opening called the ‘distribution tube’- find a screwdriver that fits the opening and unscrew the bolt inside, then gently tap the carburetor (with the narrow opening facing downward) on a solid flooring until the main jet and emulsion tube comes out.
  6. Now put on your protective gloves and eyewear and use a carburetor cleaner spray to clean the main jet. If you do not have a carburetor cleaner spray, you may use a wire.
  7. Next, use the carburetor cleaner spray to clean out the emulsion tube. When cleaning the emulsion tube, be cautious because it will spray everywhere. However, if it does not- it means it is clogged. In that case, use a needle or wire to clean out the holes of the emulsion tube.

Advise Alert: Do not reassemble the carburetor just yet! The pilot jet is located close by and requires a visit too!

How To Clean Out Predator 3500’s Pilot Jet?

  1. You can quickly identify the carburetor’s black ‘Throttle Adjustment Screw.’ This screw is never fully bolted, and the ‘looseness’ is essential for its function. Therefore, tighten the bolt and count the number of turns it takes for it to be fully tightened. This way, when you reassemble the carburetor, you will know exactly how many turns you must keep it loose.
  2. Now unscrew the black throttle adjustment screw and remove it from the carburetor.
  3. Close to where the black throttle adjustment screw was located, you will find the black pilot jet, which will resemble a plug and is easy to pull out; you can use a plier for help.
  4. Spray clean the pilot jet; however, it contains an O-ring, so be careful to avoid spraying that.
  5. Go ahead, and spray clean the hole where the pilot jet came from. Next, spray clean all the different holes and crevices in the carburetor.
  6. Reassemble the carburetor and reattach it to the generator. 

3. A Loosely Mounted Carburetor or Compromised Gasket

A carburetor that is not fully attached or has a damaged gasket will lead to your Predator 3500 malfunctioning and only being able to run on a choke.

This is because both factors will lead to an imbalance in the fuel-to-air ratio as more than the required air will be allowed to be sucked into the intake.

Therefore, check both carburetor gaskets for cracks- if you spot any, it’s time to replace them. However, if it is clogged, all it requires is an excellent deep cleanse!

Moreover, ensure that the carburetor is tightened against the intake; otherwise, a vacuum will be created in the space, consequently leading to additional air being sucked into the intake.


The saying ‘‘You are what you eat’’ also applies to generators!

The key to avoiding any malfunctions in your Predator 3500 generator is supplying it with the best quality and perfect quantity of fuel! 

Therefore, always remember to buy ethanol-free fuel and stabilize it using ‘Sta-bil’ or ‘Seafoam.’ 

Moreover, give the carburetor a spa-sesh every few weeks, so the fuel-to-air balance is not disrupted.

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