Engine Tuneup for Generac Wheelhouse 5500 / 5550 Portable Generator


I don’t use my portable generator that often, other than maybe testing it once every month or two, so in my opinion it is critical to perform an engine tuneup at least every 12 months.

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 1) and/or Part 2


Thankfully, no special tools are required. I do, however, recommend a siphon to drain the gas:



  1. Disconnect the spark plug cable;
  2. Remove old gas using a liquid siphon; I don’t recommend tipping your generator to empty out the gas because it can get messy and I do not want my electronics to soaked with gasoline;
  3. Drain the used oil by tipping the engine at about 30 degrees;
  4. Replenish with new engine oil;
  5. Replace the air filter;


  7. Remove the old spark with a new Champion spark plug with gap set to 0.030;
  8. Add fresh fuel (preferably premium or 93 octane gasoline);
  9. Add Sta-Bil to new fuel and let is sit for 30 min;


Using synthetic oil is probably an overkill, but it allows me to use the same engine oil throughout the entire year (and it is supposed to make the engine last longer) so it’s a worthy investment for me.

Thanks for reading and good luck with your tuneup!


26 thoughts on “Engine Tuneup for Generac Wheelhouse 5500 / 5550 Portable Generator”

  1. Hi Kevin, My name too lol, And I also have the exact same generator I agree on using synthetic engine oil. I’m in S Florida. What SAE Mobil 1 Engine Oil would you recommend I use? 10W30?

  2. Hi Kevin,
    I have this exact generator and unfortunately don’t have the owners manual nor have I been able to locate one on line…..do you know if there is one available?
    Cheers, Brent

  3. Hi Kev, Update on my Generac WheelHouse Generator. I gathered up everything needed to tune it up taking my time over the past two days. Not knowing the oil that remained in it, I drained it then flushed it with a quart of new Mobil 1 SAE 5W-30. Drained, added another new quart of Mobil 1. Next, there was about a half gallon of old gas in the tank. Flushed that as well, twice after looking at the new 93 octane I put in the tank the first time seeing residue after removing it. Second time I drained it the new gas was clear of any residue. Added two gallons of new 93 octane confident all that was done, ready to fire it up. Third pull, got it running. I let it run for 15 minutes. During that time I tested the load with some shop tools. Perfect. Hurricane ready here in S. Florida. And by the way, we moved down here in 2014 coming from LINY. S Shore Nassau. county. And yes I to experienced hurricane Sandy. After Irene in 2011 I purchased a whole house generator. Ran for 9 days after Sandy. Had enough of cold winters, enjoying everything we can here in S. Fla. (Palm Beach County)

  4. Awesome! My only two suggestions would be to: 1) do a full-load (maybe refrigerator, ac, etc.) and let it run for an hour or two; 2) add Stabil to your gas.

    And yeah, I attended Stony Brook long time ago so I hear you about cold winters.

    Thanks for the update and have fun in the sun!

  5. You are quite welcome. Thanks and good luck with your Wheelhouse 5550! It’s built like a tank so with little care and maintenance, it will serve you well.

  6. I cleaned the carb out on my 5500 watt wheel house now to change the oil there’s a dip stick on top that reads full then below is a yellow plastic drain plug is this a different reservoir to keep filled ,and at the lowest point on the engine there is a sguare aluminum plug should I drain the oil from that one is the lower yellow screw a different reservoir can’t figure it out don’t have a manual

  7. @ Mike-

    I think there are several different engine versions. Earlier versions came with dip sticks but the later versions did not. For those engines without dipsticks (like 5500 storm responder), yellow plug is how you check the oil level and if necessary, fill.

    I do have the manual in a pdf format available. Link is found at the bottom of this page.

    Let me know if you have any other questions.


  8. I have a generac wheelhorse 5550 generator with a Briggs and Stratton engine it doesnt start, I would like to know the motor number, any ideas cant find the useable one anywhere. I am going to replace the Ignition module because it has no spark..

  9. @patrick-

    does the engine turn over? working used motor (if you can find one) will probably cost over 200 bucks…

  10. Found your site when getting my old (but new to me and in nearly new shape) Generac WheelHouse 5500 ready for hurricane season here in TX. Hadn’t run in 3-4 years, and was left with a little gas in it. I added about 1/4 tank (looking back, should have drained out the old), and it runs, but not very well. Can’t get it off half choke without the engine dying. Also won’t handle more than about 3000 watts (electric space heaters). Any ideas? I ran it for 20 minutes or so, but it didn’t get any better. Also, I’m thinking about setting it up to use my bbq propane tank. Recommendations? I saw a high-pressure propane setup, but not one for smaller tanks (although I really don’t know the difference).
    Anyway, thanks for a great site and good info. I will be using your links for my purchases.

  11. Hi Kevin

    I did clean the carb, change the spark but still no working the new spark doesn’t work!!!

    Any ideas???

  12. I have this same generator and have owned it since it was new about 17 years ago. It has been an incredible workhorse as I lose power here in Maine approx. 4-6 times a year. I start it up monthly and let it run for about 10 minutes and then turn the gas off. Once the gas has run through the carburetor it dies. This keeps the fuel from separating in the carburetor. When I fuel it up I add marine Stabil which is used to protect small engines from ethanol. 2-3 times a year I put some Seafoam in the gas as well to help keep the carburetor clean. Every fall I change the spark plug, air filter and oil. If I have to run the generator more than 24 hours straight I change the oil at the end of the event.

  13. Hi Dave-

    Yeah, I wish I kept that one instead of replacing it with Briggs Storm Responder 5500. Wheelhouse 5550 was built like Fort Knox, heavy frame, heavy duty components, etc.

    The only suggestion I would like to make to you is to put some load (i.e. refrigerator or washer) on your generator when testing. Lots of professionals recommend loading testing. For example, REMInetwor sas “…turning on a generator without a load attached is like turning on the ignition in a car left up on jacks in a garage for a long time and leaving the car in park. There is no way to know if the vehicle will operate on the road. Just hearing the motor run doesn’t mean the car can be driven or the tires are aligned…”

    Hope the winter in Maine wn’t be too bad this year. I have to go back to Acadia!


  14. Hi Kevin. I have the same exact generator. I’ve had it for a while now. But I’m having problems for the last couple seasons. My on off switch does not work. I have to unplug the black wire for it to start. Then plug it back in. I’m not even sure I have the red and white wire in there correct locations since so many hands have been trying to fix the problem. Help!

  15. Hi Kevin. David here. What I meet to say was. I then leave the black wire off. When I want to kill the engine I plug the black wire back in.

  16. Hi Kevin,

    where did you get the carb rebuild kit? I’ve seen several places that sell this kit but the reviews have not been great on these rebuild kits. What’s the part number for the rebuild kit?


  17. Hi Benny-

    I presume we are talking about Generc / Briggs & Stratton Wheelhouse 5550?

    If you are looking for an overhaul kit, this (link) is the OEM part I have used in the past. What I would do is also to purchase the OEM replacement carb at the same time (link).

    That way when you take apart your carb and see its condition, you can decide to overhaul or replace without losing time (and return the unused part).

    Just a note, if you have never worked on a carburetor before, its not hard but requires some specialized tools. Make sure to read my posts.

    Good luck and let me know how you make out.


  18. Thanks a bunch for the info ~~ I am prob behind a few years , but still working with the 5500. I tried to print the owners manual , but NO print. Do I need it?
    The springs and wire parts are all rusty ~~ I wonder how to handle that ~~ none in two , but rusty ~~ I wonder if any spring replace kits to care for this?
    Whats to do?
    It would be better to for ME if You would use direct e-mail ~~paulspic@yahoo.com

  19. I found the owners manual for the generator but not for the engine. Do you have a link for it? Also, how many quarts of oil does it require?

  20. Hey Dan-

    Unfortunately I was never able to locate the engine manual…..engine takes slightly more than 1 quart so after draining and capping the plug, add oil about 3/4 quarts then check the dipstick before adding more.

    Did you have a specific problem with your engine?


  21. Thanks Kevin. Just trying to do the first real maintenance on it that I know of. I purchased it used 6 years ago and the only thing I have ever done is put a little fuel in it once per year, start it until it runs out of gas, and then put it away. Now I just used it for several days and nights in a row during the TX power outage. I want to make sure it runs well the next time I need it and I noticed I was having to run it on half choke. I am replacing the air filter which appears to be much of the problem. Also replacing the spark plug now. My big problem is I cannot get the carburetor bowl off because one of the screws is rusted on. I want to clean it out. I also can’t get the idle screw to turn without almost stripping out the head.

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