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


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.

Hurricane Season officially begins June and ends on November. Please check and service your portable generator well before June, especially if you have not recently tested your generator.

Although 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.


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 will 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, you need re-use the choke handle bar because the new one is shorter than the original one (this involves simply removing a choke plate).

Nikki 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.

For about 15 bucks cheaper, you can also look at this replacement carb. I have personally not used this part though.


Overhauling a carburetor is more labor intensive process and may not be a good solution if you need to get the generator up and running and you need to do other things to get ready.

I am going to share my detailed step-by-step instructions with you so that if you have some spare time,


I think you can agree with me that spending 100 bucks for a new Briggs & Stratton Carburetor Part # 591378 is far cheaper than buying a new generator


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.



If you don’t want to purchase the kit, you can buy these individual components separately (but will not be as cost effective):



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!


99 thoughts on “Fast and Easy Fix for Your Generac Wheelhouse 5500 / 5550 Portable Generator”

  1. How do you know that gas is not flowing from tank to quik connect? Is there something that is lodged inside fuel line?

    Besides, even if you run it dry, there is always some gas left inside the carb fuel bowl. I would take apart and clean the carburetor.

  2. When I take the Quik connect hose line off I am able to get gas flow out of tank. It am unable to get air flow out thru that hose line and their is no visible obstruction. And What I meant was a trial run while it came out of box with a tank of fresh gas.

  3. depending on how you stored your unit, your hose may have degraded over time. Double check but I think that hose is 3/8″ ID. You should be able to find one at your local auto parts store.

  4. I’ve purchased a disassembled Generac Wheelhouse generator. It’s together but for some wires i have no clue where they go. these wires are on the plate that sets where the Governor arm is.. Any help is needed.

  5. can you take a picture of your setup and send it to me? info (at) allthumbsdiy (dot) com

  6. @Roland-

    I am having issues with my email server so I am posting my reply here instead:

    Hey Roland-

    I sold my Wheelhouse 5550 to my neighbor few years ago. I thought I had some unpublished pictures that may help you but I could not find any.

    I do, however, own Briggs 5500 Storm Responder that is almost identical to Wheelhouse 5550 so I took off the cover and took some pix.

    One thing I did notice was that your setup had three wires, where black and white wires are joined by a relay of some sort (plus the red). My setup has two (black and red).

    Hope these pix helps. let me know if I can help you with anything else.


  7. Tnx Kev, This gives me a good start to follow thru to fruition. I’ll finish off in the am and giver it a go.

    Tnx agn. Rollie

  8. Are there things we can try before doing a carbureator overhaul? Mine started up fine after 8 years, but quits after about a minute. I did not leave gas in it.

  9. Hi Tom-

    There is always a bit of residual gasoline left behind , even if you run until dry.

    I would suggest to at least remove the fuel bowel from the bottom (I would recommend you have a replacement gasket ready) and try cleaning it from bottom up using a carb cleaner but I have to warn you, it;s messy and I could not really clean the parts thoroughly.

  10. Kevin:
    I was in contact a while ago ~~Generac 5500 with B&S Nikki carb
    I got the carb back together , but need connections from carb to gas tank. All those connections and now I need a replace. gen runs when I squirt fluid in , but need connections from tank to Gen / carb ,
    Any Show and tell of them? connections parts from tank to carb? Carb/ seems to be free now. and clean )
    What number Is the overhaul kit for Nikki carb (just in case )

  11. Paul D ~~ still have the 5500 ~~ W / Nikki Carb, I worked on the carb , The movable flap inside did not move , locked after lots of hammer and etc got it out and bent it. After straighten it back it was too big so I filed it to fit loose . Is there a way to check to see what if it works and how it works? It ran with squirt of fuel in ~~ not sure but I have a rubber line 1/4″ with a filter which I can attach ~~ I got an V/W taper clear filter with a big end and little ~~ (not sure which end goes to tank and which for motor.
    I have never had to use it ~~ but the latest flap Jan 2017 got ME to thinking about having it ready. Is there any way to have and keep MY unit ready for use , without having to do major surgery ? Just have it ready for use. Our power may go out about every 5 yrs or so.
    The used part mowers just burnt so not sure a supply for a spare carb now. Guess a Craigs list or e-bay now. (Later)
    Any advise bout the flap ( How it works and any adjustment) and if any advise on carb? Does it come with a rebuild kit?
    Thanks for advise .

  12. Hello Guys, I am not sure if anyone is still following this thread but I have a question.
    I have a Wheelhouse 55oo 01641-3 and cannot get any spark. is there a service diagram for the motor?


  13. @ Hi John-

    You can peruse through the reference links but I don’t believe there is a service diagram for the motor.

  14. Your a life Life saver I could not find info anywhere else, Hurricane Irma on the way and generator was dead.. It took a bit more time than i thought , but she is running like a champ now.

    #amazon had the parts here in time!!!!

    THANKS !!!!!!


  15. Wheelhouse 5550: A year ago I disconnected the gas tank by way of quick disconnect and had it filled with gas. I reassembled the tank but did not start or run it because it was no longer required. In preparation for Irma I am unable to keep my machine running after about 10 seconds. Moving the lever to open choke or run position cannot be achieved.
    After disconnecting to see if fuel was coming out of right hand part of disconnect but it was not. Removing that part from hose the fuel did flow. In desperation I removed the “guts” and reconnected only to find. that fuel will not flow from the left hand part of the disconnect.
    Other then replacing the quick disconnect can you offer any other advice? Also, what other function does the disconnect serve and where can I purchase it? Please advise.

  16. @ Howard-

    Part numbers for the quick disconnect are (link to amazon is provided):

    It’s my understanding that the purpose of a quick disconnect is to allow the user to change the gas tank quickly. Personally, I never used this feature. I waited until the engine cooled down to refuel and start up again. If you need the generator now and are willing to forgo this feature, you should be able to find a longer fuel hose (I think it’s either 3/8 or 1/2) at an automotive parts store.

    good luck and stay safe!


  17. @ John-

    My guess is that you have fuel mixture leaking out to exhaust where hot surface ignites it causing fire.

    There are lots of potential problem areas but I would start with cleaning the carb, replace spark plugs and air filter.

  18. i was also about to ask which oil but saw the comment. silly question- how do i drain the old oil to change it? thanks in advance

  19. Hi Andy-

    The oil plug has a small square head with red thread locking compound. It is located on the bottom of the engine that is opposite side of the oil dip/fill cap.

  20. My name is john my 5500 runs for about an hour than dies over and over starts right back up every time and dies any help

  21. @ John-

    How often does it happen? Does is run rough just before dying? Do you keep left over gas in the tank when not in use?

    Not knowing the details of your generator, I would look at your gasoline + fuel hose first (get rid of it and refill with high octane gas to see if you can replicate the problem). If not, I would take apart the carb and clean it before doing anything else.

  22. My generac 5500 runs good, a little fast at idle, but is putting out too much power. Is there an external voltage regulator, or how can you adjust the power output?

  23. @dudley

    i don;t believe generac 5550 has an adjustable voltage regulator. how did you determine that genny was producing too much power? is it producing too much at idle or at full throttle?

  24. My 5550 has been solid as a rock for years. Always starts on first pull. This time won’t start at all. Ohm meter tells me the black wire from on off switch is grounded even when disconnected from the switch. That wire goes inside engine. I would like to know that could happen and how to fix it

  25. Hello, I am on the East Coast and recently did battle with Hurricane Florence. I have a Wheelhouse 5500 and have never had a moments trouble until today. I had run it for several days supplying power to my home. After power was restored to my home I lent it to a friend and it stopped running. I went over and gave it time to cool down. After cooling down, it started but ran poorly and then stopped. I am thinking that the ignition coil has gone bad………any thoughts anyone? The oil level was good, plenty of gas and plenty of good clean air…… just won’t run for more than 15 seconds. HELP

  26. Hey Gregg-

    It sounds like the carb is starving for fuel. if it cuts out after starting for 15 seconds, my primary suspicion would be the air filter, fuel or carb.

    Here is what I would do:
    0. Make sure the fuel shutoff valve is not turned off!
    1. Take out the air filter to make sure that it is not wet; if it’s wet, try starting the genny without it; if it starts, you need to buy a new air filter
    2. Did your friend mess with the genny settings at all, other than starting it? did he change the setting on the carb fuel mix screw? if yes, ask him to show you exactly what he changed and reverse it
    3. Drain the fuel and replace it with fresh high-octane gas from a KNOWN reputable gas station that stayed dry; you need to siphon out the gas but don’t be lazy and skip this step; using stale gas (which has higher moisture content) will make it hard to run your genny;
    4. Lastly,dDisassemble the carb and clean it using my instructions found in this post

    I know it’s overwhelming with everything else going on, but try to focus on one area at a time; unless your friend did something stupid like overloading the generator, most electrical components are made very well so it shouldn’t be a problem; look for simple issues first.

    Let me know how you make out.


  27. I have one of these wheelhouse generators, had to use it on 2 occasions for a total of about 17 days. It always ran perfect and started immediately. I had always started it at least twice a year to let it run and get some fresh fuel(with stabilizer) into the carb. Later I purchased a generator with more capacity . So I was going to sell the wheelhouse to a friend. When I tried to start it it would not start . I pulled on the rope until I flooded the engine. Let it sit with no spark plug over night. Next day same thing. When I checked the plug for spark there was none. I checked the oil level it was fine, replaced the plug , checked the on off switch. All were fine, still no spark, what ‘a next ? Coil?

  28. my 5550 had run perfectly for 2 yrs, when i tried to run it recently it would only run on choke. i took the
    carb off and it looked clean. i ended up ordering a carb and a fuel shut off kit.
    runs ok now, but it surges. any ideas ?

  29. Hi Mike-

    If your genny is surging without any load on it, I would siphon off old gas and replace it with high octane gas.

    If it runs well with high octane gas, let is run for 30 min without any load. It is very easy to contaminate gas (i.e. water condensation).


  30. yeah, coil would be the next logical step. but keep in mind that wheelhouse is getting pretty old at this point so components will start to fail…

  31. Thanks for having the manual for the generac 5550 generator. Lost ours and this is very useful!

  32. Glad it was helpful to you.

    Generac 5550 is getting up there in age so I would recommend switching the oil to synthetic and use higher octane gas.

  33. i cant find parts for mine. the one i have is missing the air box, the blower housing and the pull start

  34. Hey Kris-

    because Generac Wheelhouse 5550 is 20+ years old, you probably will not be able to find parts like that from a store. Your best bet is to look at Craigslist / OfferUp / Ebay.

    Good luck

  35. Hi, I’m getting a lot of oil in the air filter. What might be the cause? Thanks

  36. I have one with a bad coil. I can’t find the engine code anywhere to start to get a replacement part.

  37. engine code is usually by the carburetor. which specific model do you have?

  38. I’ve had mice make a nest inside the starter cover and the on/off switch cover on my Generac 5550. The black wire under the on/off switch cover is connected to the switch but the other end is loose. Can anyone tell me what that should be connected to?

  39. Hi Dana.

    I no longer own Wheelhouse 5550 but have Storm 5500 which is almost identical. I will take a look tomorrow morning and get back to you

  40. I was short on time so I could only take one picture…I will see if I can take a better picture tomorrow..

    Storm Respnonder 5500 - Black wire

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