Fast and Easy Fix for Your Generac Wheelhouse 5500 / 5550 Portable Generator


WARNING – Working on a generator means dealing with gasoline, gasoline vapor, various solvents, etc. Please work in a well ventilated area, away from any sparks or heat and wear appropriate safety devices.

So my Generc Wheelhouse 5500 / 5550 generator has been sitting in my shed for years without seeing much action (I was supposed to do a monthly test). Well, then it was no surprise when Hurricane Sandy was approaching (October 28, 2012) and I could not start my generator.

Although I was fortunate enough to purchase a new Briggs and Stratton 5500 Storm Responder at the last minute (another story) and I would hate to think how my family would have been negatively impacted if I did not have a generator during a long power outage (we lost power for 14 days).

While my new generator was up and running, I searched the internet was able to get my Generac generator to work with some simple fixes so I thought I would share that information in case you need it.

A special shout-out goes to DIYchatroom members Bondo, DexterII, oh’Mike, joecaption and Missouri Bound! (posting can be found here)



Here are some of the symptoms I’ve experienced with stale gasoline.

  • Engine starts but quits running after 10-15 seconds
  • Engine does not start but gas leaks from the air filter
  • Engine will start only for few seconds with starter fluid
  • Engine will run rough under full choke but dies when choke is opened
  • Engine sputters, guzzles gas then dies


Did you know that gasoline goes stale after only 30 days (from the date of manufacture)? Couple that with some unscrupulous gas stations selling contaminated fuel, it’s no wonder some generators refuse to start.

Stale gas tends to create what looks like red rust which deposits on to internal components like the float, needle valve, emulsion tube, etc. Many of these components are small and have even smaller orifices which would easily be clogged, preventing your engine from running properly.

Obviously, there are other causes but the scope of this article is to get the Wheelhouse 5550 up and running by fixing problems caused by stale gasoline.

Game Plan

Since my generator has been sitting around for awhile, I decided to do some basic tuneup by replacing usual parts like air filter, spark plug, etc. This way, I was fairly confident that my problem was isolated to a carburetor build up.

Please note that Generac Wheelhouse 5500 / 5550 Briggs and Stratton engine may contain either Walbro or Nikki carburetor. Since my generator came with a Nikki carb, the article will only cover this particular carb.


Walbro Carb


Nikki Carb

These diagrams can be found in page #4 of the Illustrated Parts List – Model 31c700 document.



Basic Tuneup FIRST

When I was in a hurry to get my generator up and running, I did not have the (time) luxury of troubleshooting each components. Rather, I did a quick replacement and tuneup using these components.

  • Replace the spark plug (gap set to .030)
  • Replace old with new fuel (premium or 93 octane preferred)
  • Add Sta-Bil (for gasoline) to new fuel and let is sit for 30 min
  • Replace Air Filter
  • Change oil (SAE30 during Fall/Winter or 5W-30 during Spring/Summer)

Step-by-Step Guide to Cleaning a Nikki Carburetor

Make sure to work in a well ventilated area. Place some sort of protective covering under the generator (I used a heavy duty trash bag) to protect the surface from fuel contamination and unless you like gas smelling hands all day long, wear a pair of Nitrile/latex/vinyl gloves.

Also, please note that pictures were taken during two separate times so some parts (like a fuel bowel) may not match the instructions. Please follow the instructions.


I attempted to clean the carburetor with it still attached to the engine but quickly found that I was not able to thoroughly clean it. In addition, the internal O-ring was virtually impossible to mount without the carb being upside down.

STEP 1 – Turn off the fuel supply valve (fig.1.1)
STEP 2 – Using a TBD” socket (try one of your mini ratchet sockets. I will update the size later), remove two bolts holding the air intake cover. Remove air filter (fig.1.1 and 1.2)
STEP 3 – Move the choke lever to CLOSED position. Make sure the handle notch is lined up with a small notch on the metal plate and gently pull up the handle (fig.1.3). DO NOT use excessive force. If it does not come up, double check to make sure notches are lined up.
STEP 4 – Using a TBD” socket (try one of your mini ratchet sockets. I will update the size later), remove two nuts holding down the metal air intake shroud. There is a rubber hose attached in the rear, upper left corner. Gently pry it off (fig.1.4 & fig. 2.1).









STEP 5 – Using a pair of pliers, squeeze the hose clamp to open (fig.2.1). Move it up so that the fuel hose can be removed from the fuel inlet (fig.2.2). Gently pry off the hose from the fuel inlet (expect some gasoline to drip out)
STEP 6 – Using a TBD” socket (try one of your mini ratchet sockets. I will update the size later), remove 2 bolts holding down the carb to engine (fig.2.3). These bolts are SOFT BRASS. DO NOT use pliers to try to remove these bolts as you will crush the ends.
STEP 7 – While holding the detached carb in one hand, slightly rotate it to gently unhook the governor spring wire (thin) and a throttle linkage cable (thick) (fig.2.4).









STEP 8 – Using a flat (slot) head screwdriver, remove two screws and washers that are holding down the carb fuel bowel (fig.3.1). Be careful as it will hold about 2 oz of gasoline. Also, there will be a loose spring inside (fig.3.3). This is what keeps the internal plastic components (float, gasket-float bowel) in place. Make sure to keep it in a safe place. Note how in fig.3.2, you see reddish deposit on the bottom with some flakes. These are deposits from a stale gasoline. Use a small amount of carb cleaner to clean them as much as possible.









STEP 9 – A large plastic piece that is now visible is called a float (fig.3.4). Carefully slide out the hinge pin using a straight paper clip. One end of the hinge pin is crimped so it can only slide out in one direction so if you cannot easily slide it out, try pushing it in the other direction.

Once the float is detached, you will see a small gray “needle valve pin” (fig.3.5, fig.3.6 and fig.3.7). This needle pin either opens or shuts the fuel valve so that tip needs to be free of any debris. Be careful as the tip is made of rubber and it will pop off easily (and very easy to lose!). Using some fresh gasoline mixed with carb cleaner (2:1 ratio), clean off all gunk (as stated previously I do not like using straight solvent on plastic pieces as it may degrade the plastic components) so what I did was to dip some cotton swabs in the mixture clean off the gunk. Fig.3.8 is the end result of that cleaning which took about 20 minutes.









STEP 10 – The remaining round plastic piece (gasket-float bowel) channels the gasoline flow. Note how the inlet and outlet ports are clogged with junk (fig.4.1 and fig 4.2).
STEP 11 – The inlet also has a small (ceramic) piece with an O-ring that gets open/shut by a needle valve (fig.4.2 and fig.4.3). Gently pop it out by using a Q-tip with firm force. DO NOT use an awl or any sharp, pointed objects which can enlarge the hole or worse, crack it.
STEP 12 – Using a thin wire, clean off as much gunk as you can, not just the hole but all surrounding area (fig.4.4) If there is gunk left, needle valve cannot seat properly which will flood the engine (which is what happened after my first clean attempt).









STEP 13 – This is what it looks like after thorough cleaning (fig.5.1 and fig.5.2).
STEP 14 – To pop the ceramic flow control piece back in, I used a small piece of leftover 12 AWG electrical wire. You can also use a Q-tip, but make sure you hear the “click” to ensure that the O-ring has been seated properly.
STEP 15 – On to cleaning the carburetor itself. VERY Carefully remove the O-ring seal and put it aside (Fig.5.3; BTW, if you are attempting to clean your carb that is still attached to the engine, it will be fairly impossible for you to re-mount this O-ring so you may *not* want to remove the O-ring).
STEP 16 – Using a carb cleaner, carefully and thoroughly clean all holes and grooves (I also used Q-tip to scrub the gunk off). Pay special attention to the inlet port where fuel enters the carburetor chamber. I ended up using Q-tips soaked with straight carb cleaner (no plastic inside the carburetor) to clean the inside, making sure to not leave behind any Q-tip remains.

Carb cleaner can unexpectedly shoot out in different directions or even deflect back at you. Make sure to WEAR EYE PROTECTION and preferably a long sleeved shirt










STEP 17 – Now that all parts have been thoroughly cleaned, it is now time to reassemble the carburetor and re-attach it to the engine. Just use reverse steps to reinstall, making sure to install the retainer spring before seating the fuel bowel (fig.6.1 through 6.8).

















Once you are done, turn on the generator switch (marked as “ON” or “I”), open the fuel supply valve, set to full choke and pull to start. Hopefully that will get it to start up right away! My older generator actually sounds like it runs much better than my new Briggs and Stratton generator!

Portable generators produce lots of carbon monoxide that is colorless, tasteless and does not smell. Follow the manufacturer’s instructions to keep it away from your house and make sure your carbon monoxide detectors are positioned near it


Well, that’s all there is to it. If you are unclear about my instructions, please feel free to post your question in the comment section. While at it, if you found this article to be useful, please sign up for my newsletter.

Thanks and good luck!



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    1. John says

      This article is great.

      I had my generator that sat in my shed for 5 years without being used. of course when I needed it, it did not start (no surprise there).

      I was able to follow your directions and cleaned the heck out of my carb parts to get my generator to start.

      In spring, I plan on following rest of your directions to do a complete tuneup.

      thanks again


    2. Brett says

      I just bought a gently used generac wheelhouse 5500 just like the one you have pictured and i would like to find out the date the engine was built and any other engine info so i can get replacement parts for it if i ever need to but i cant find the date code anywhere on it and all i can find is model number and other info on a sticker on the grey shield next to the muffler, can anyone please help me find the date code on the engine?


    3. kevin says


      I believe engine date codes are stamped on the alternator housing but it needs to be de-coded.

      Have you called the Generac customer service toll-free number at 1.800.270.1408? I am sure they can look it up using your serial number.

      Also, if the unit has not been used for awhile, you should drain the old gas and replace it with new gas, and disassemble and clean the carb.

      Let me know if you need help


    4. Brett says

      Thank you,i found it, it is under the chrome ohv cover and i already drained the gas and changed the oil to a full synthetic 10-30 motor oil and i would clean the carb but i need to read up some more on what carb i have plus i need to get the courage to tear into it.

      Thamk you for the fast response and great website.

    5. kevin says

      nice. wheelhouse 5550 is a sturdy, reliable genny. with a little maintenance, it should last a very long time.

      at the end of my article, there should be some links to pdf files that should help with your rebuild.

      good luck with your new generator!

    6. jeff says

      How much oil typically goes in the wheelhouse 5500? and what type of oil is best?

    7. kevin says


      That is an excellent question and I never found an answer for it. If you are using 5550 Wheelhouse, it has a traditional dipstick so I used to put in little bit of time until the stick indicated the oil was at a proper level.

      For the 5500 (the newer version I currently own), it did away with a dipstick in lieu of a plug. What I did was to fill up with new oil just below the threaded hole (that was the factory oil level). Can’t remember the exact quantity but I think it was about half quart.

      As far as the oil viscosity is concerned, I would use SAE30 during Spring, Summer and Fall. During the winter, change it over to 10w30. Of course, if you have cash to burn, you can put in the synthetic 5w30 that can be used all year around.

      Just make sure to fire up your generator every month with some load on it and run for 30 min. or so. With storm season already in route, you don’t want to be caught shorthanded like I did last year.

    8. Lisa says

      I am trying to change the choke handle cord on my power boss 5500 generator and cannot get the cover off to replace it. I bought the new cord and need to get the facing off of the generator. It has star shaped alley key screws (they are stripped) and they will not come off. What can I do to get the screws out to fix my generator ? Please help ASAP!

    9. kevin says


      Hi there-

      I think all DIYers have experienced stripped screw heads at least once.

      Fear not, they make nifty extractors for this purpose! I highly suggest Alden 8440P Pro Grabit Broken Bolt and Damaged Screw Extractor 4 Piece Kit due to its metal strength and durability.

      Please, please avoid any 5 dollar sets from Harbor Freight as they will cause more headaches!

      Good luck and please let us know how you made out.


    10. kevin says


      thanks! make sure the generator is in top shape (and have gas on standby) with this crazy winter!

    11. john says

      That all good but there are many articles on working with Briggs engines but none address actual generator side charging and electric output etc.??

    12. kevin says


      Most of the articles are based on things that need to be repaired as I experience them. I’ve been lucky in that I have not experienced any electrical output issues. Are you having trouble with yours?

    13. says

      Getting my Generac Wheelhouse 5550 Briggs & Stratton Heavy Duty Generator to start up again after sitting idle was a breeze following your instructions for cleaning the carburetor. Saved me at least $95.00 for a shop visit! Thank you for this post.

    14. kevin says


      Awesome! Thanks for letting me know.

      BTW, make sure to test your generator at least once a month with some electrical load.

    15. Ron Ritchie says

      I have a wheelhouse 5550 for ten years and have had no problem with it until 6/4/2014 during n power outage. My wife is on an oxygen concentrator and I had to get the generator running asap. It started and I had her up running , but an hour later when the power came back on I went to turn off the generator and smelled gasoline. Gas was coming from the air filter to the ground. I quickly water the area down to prevent a fire. I was lucky.
      I bought a new generator the next day and would like to fix the Wheelhouse cause it is a good machine. Where can I find a service center in the Edinburg/McAllen , Texas area?
      thanks your article is great I just don’t have time to work on it.

    16. kevin says


      Thanks for your kind comments. Unfortunately, I am not familiar with that area.

      Best wishes

    17. kevin says


      Glad to hear you were able to get your generator up and running!

    18. Joe says

      Using same unit. Ran fine till I cleaned carb prior to storage. Now govenor forces throttle to full upon start and remains there. Seems like I had to have lost a spring in the govenor linkage but I see nothing else wrong. Could you e-mail a pic of your govenor linkage uncovered so I can determine where the problem is? No help from parts list since it covers variable units.

    19. kevin says


      I ended up upgrading to a Briggs and Stratton Storm Responder 5500 so unfortunately, I cannot take additional pictures.

      IIRC, the Wheelhouse 5550 genny had a mechanical governor so I think you should have both a spring and linkage to control the carb throttle under load and stalling under no load.

      For some diagrams, you may want to read the Small Engine Care & Repair: A step-by-step guide to maintaining your small engine (Briggs & Stratton) book. The Wheelhouse 5550 has a B&S engine, so the materials in the book should help you.

      You will probably need to contact B&S with your engine code to get any missing governor linkage and/or spring, however, as they are hard to find.

      Good luck and let me know how it turns out.

    20. eric says

      Great article you wouldn’t know where I can get the replacement Nikki carburetor by chance mine is bad

    21. DJ says

      Halfway thru removing the carb from my 5500

      Having plenty of issues

      What is the size of the torx socket to remove the long bolts on the carb

      Thanks – this site encouraged me to take it apart

    22. kevin says


      I didn’t have that particular torx socket so I just used a regular 4 mm socket to remove those 2 long bolts. I knew if I put a lot of stress on it the first time, I could strip the head, so I just took my time and incrementally applied force to the bolt, while generously injecting WD40 around it. Good luck! PS. Make sure to wear goggles!

    23. says

      Info Mdl 01646 Generac B&S Engine ~~
      Wish I had of known this stop or found it BEFORE > Hopeful the carb its all there now and back together right ~~ some operations I was not aware of ~~it was a hit and miss before. Like the needle valve clean rubber end and jet out with o-ring and hole to open) (need a makk system to line up for install in carb housing. ** Hint not a magic marker cause of gas /carb cleaner.
      A new carb is hard to get an exact replace for. a Nikki carb Mdl 695114 GO 2502 1 X 23A (stamped on carb)

      My carb had to have butter fly hammered punched out (after 2 screw disk was removed)
      (Only * One way it comes out , to get it out ) only if its locked and does not flap) )
      I have not found a replace kit or carb with this in the kit )
      I sanded and scraped to get areaS cleaned.
      HINT # 1
      I discovered a helpful idea , ^ a common nail (head first) the right size for the hole , scrape with the nail < head < (makes a great scraper .
      HINT # 2 ~~
      *ALSO a piece of guitar strings for small carb holes. Diff strings for diff size holes .
      Good luck
      Thanks for the great information. Wish it had been an "OPEN here first". Diff brand of carbs too with a print info for each.
      Also need a pic and description of gas lines and connections and cut off noted. .

    24. kevin says

      Thanks for the awesome info. I am bit curious though. Was your Nikki carb different that what I showed you in the article?

      My memory is bit fuzzy but I recall speaking to B&S tech and he told me there were only two carbs: Walbro or Nikki with no sub models under each brand.

      Anyways, I hope you can get your generator started!


    25. John James says

      When my generator refused to start after a winter shutdown, I wasn’t surprised. “Stale/water in fuel” thinks I. Drained tank, cleaned bowl……..still no luck. In desperation, went looking on the Internet. Found your site. Followed your instructions and sure enough, found three goats and a family of gypsys living in one of the float chamber tubes. Now my machine runs great! Much good will going your way. Especially with the hurricane season coming on. Thanks…….

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