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


Hurricane Season officially began on June 1, 2015 and will end on November 30, 2015. Please check and service your portable generator now, especially if you have not tested your generator recently.

My Generac Wheelhouse 5500 / 5550 generator (made by Briggs and Stratton) was sitting in my shed for years without seeing much action. I knew I had to test it every month but without any need, it was sort of forgotten and unused. So when it refused to start with Hurricane Sandy bearing down us, all I managed to do was flood the engine when I repeatedly pulled the starter rope.

allthumbsdiy-generac-5550-wheelhouse-repair-component-dia-flAlthough I was fortunate enough to purchase a new Briggs and Stratton 5500 Storm Responder generator from Home Depot at 3 AM, I shudder at the thought of not having electricity with 2 young children (by the way, my electricity was out for 14 straight days).

While my new generator was up and running, I was able to get my Generac generator to up and running, thanks to Internet and some fine folks at DIYChatroom (thanks again guys!).

I wrote this article to capture what I learned in hoping that it might help someone else to get their generators up and running.

If you found this article via search engine, you may want to read Fast and Easy Fix for Your Generac Wheelhouse 5500 / 5550 Portable Generator (Part 2)


There are 2 main problems you may face with a generator that has been sitting around:

  1. Generator runs fine but there is no electrical output
  2. Generator runs poorly or does not start at all
    • Engine starts but quits after running for about 10-15 seconds;
    • Engine does not start but gas leaks from the air filter
    • Engine will only start for few seconds with a squirt of starter fluid
    • Engine will run rough under full choke but dies when choke is opened
    • Engine sputters, guzzles gas then dies

If there is no electricity, you may need to field flash your generator or troubleshoot the automatic voltage regulator (AVR). Please see my other post titled “Troubleshooting a Portable Generator with no Voltage Power Output” (LINK -TBD)


Briggs and Stratton engine found in Generac Wheelhouse 5500 / 5550 generator came with either a Walbro or Nikki carburetors.

Information in this post pertains to only Nikki because my particular Generac Wheelhouse generator came with it (B&S OEM part # 697978 G02523 4312 A).


Generator’s inability to start of remain running has lots to do with old, stale gasoline. Most research I’ve read indicates that the gasoline goes stale after only 30 days after it is manufactured. After 30 days t starts to form varnish that looks like red rust flakes. Varnish tends to stick and clog internal components like a needle valve, emulsion tube, etc. where tiny holes are critical for the engine to properly work properly.


If you don’t have the time for an overhaul / rebuild (i.e. a storm is coming!), you may want to buy a replacement Briggs & Stratton Carburetor – Part # 591378.

Installing a replacement carburetor is basically a drop-in that takes less than 20 minutes. If you do buy one, please remember to save the choke handle bar because you will need to re-use it.(you will need to re-use the old one by removing the choke plate; see below, right image).

Nikkie Carb Part #697879 has been discontinued and official replacement part is not available. Although the packaging on the new carburetor #591378 does not state that it can replace #697978, it works.

Amazon has it for around 100 bucks, which is way cheaper than buying a new generator (Buy Briggs & Stratton Carburetor – Part # 591378 here.


I had three choices in trying to solve my problem:

  1. VARNISH REMOVAL – Costs may be $10 or under; least expensive route but may develop leaks if old gasket is damaged during cleaning process
  2. OVERHAUL – Costs about $25 for an overhaul / rebuild kit
  3. REPLACE – Costs about $100

I ultimately chose to go with option #2 because I felt confident that my generator will be working after the engine tuneup (replacing air filter, spark plug, oil change, etc.) + overhauling my carburetor.




My next post will cover engine tuneup and Nikki carburetor overhaul (UPDATE: Fast and Easy Fix for Your Generac Wheelhouse 5500 / 5550 Portable Generator (Part 2)

Please don’t forget to check the reference links as this section contains links to lots of useful information that are not easily found on the internet.

In the meantime, if you found this article to be useful, can you do me a favor and sign up for my newsletter? The signup form is found at the top of the screen on the right side.

Thanks and wish me luck!





  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 used e5 external torx bit to remove those 2 long bolts. If you don’t have that torx bit, you can try 4 or 6mm socket but be aware that if you put a lot of stress on it the first time, you could strip the head.

    patience is a virtue :) ps – don’t use any pliers on those bolt heads either!

  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…….

  26. Joe says

    Very informative. Thank you for taking the time out to show the step by step process for cleaning/rebuilding the Nikki carb. Have you considered converting the generator over to trifuel? I think it would be really helpful to have the option to use different fuel sources.

  27. kevin says

    Hi Joe-

    Thank you for your kind words. In regards to your question about a tri-fuel conversion, yes, I actually have a conversion kit sitting in my garage. Please sign up for my newsletter so that you can be notified when I post it within next few weeks!


  28. Kevin says

    I have been unable to find a parts list showing the hose running from the air intake area to what I assume is a valve cover. Any ideas?

  29. Mark says

    Hi Kevin.

    When I select the link for a new carb the amazon page suggests that I put in model number. My generac wheelhouse 5550 has a model number; 01646, but that isn’t recognized. Can you advise?

  30. kevin says

    @Hi Mark-

    Maybe your browser cookies are interfering for some reason> Please try clearing them and copy and past this link to see if if works:

    Prior to purchasing, please my entire post to make sure that your carburetor is made by Nikki, not Walbro. The link I gave you is to replace Nikki carbs.

    Please let me know if you have any other problems.


  31. Mark says

    Hi Kevin.

    Thanks for the prompt reply. It’s definitely a Nikki. I’ve removed it twice for cleaning so I say the name. Your link works fine, but at the top of the amazon page it suggests that I verify it’s the right one by entering the model number. When I enter my generator model # 01646 the response is that it’s an unrecognized number. I had the same thing happen on Weird because the number is right there on the tag. I guess I’ll order the carb since it’s a nikki.

  32. Mark says

    Hi Kevin.
    It turns out that since Generac used a Briggs and Stratton engine they (Generac) are no help at all with engine information. I finally got in touch with a rep from Briggs and figured out where my engine model # is; etched onto the OHV plate near the exhaust. With the engine model ID the rep told me that the replacement carb is their #591378. I just found that the current carb part # is also visible on top of the carb and mine says 697978 so I guess I can use the one you linked to on Amazon.

    We’ll see how this all goes. Thanks for your help. Really nice tutorial!


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