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.
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.
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.
These diagrams can be found in page #4 of the Illustrated Parts List – Model 31c700 document.
- Mini socket set – I normally do not like Husky tools but this will suffice for light duty work (Husky 19-Piece 1/4 in. Drive Socket Set 010-012-HKY)
- Socket extenders – I recommend this (Neiko Pro-Grade 9-Piece ‘Wobble’ Angle Extension Bar Set – 1/4, 3/8 & 1/2-Inch)
- Nitrile gloves
- Drop cloth and/or plastic sheet
- Adjustable pliers
- Couple of plastic bowels + paper towel
- Thin wire – thickness should resemble a “repair tag” or “for sale tag” wires. I used a wire tie and stripped off the plastic outer sheathing
- Lisle 67870 Spark Plug Gauge Gap Tool
- Spark Plug – Champion Spark Plug RC12YC or Autolite 3924 Copper Core Spark Plug. Using a gap tool, set the spacing to 0.030 inches
- Air Filter – Briggs & Stratton 491588S Flat Air Filter Cartridge
- Carb Cleaner – Briggs & Stratton 100042 Choke / Carburetor Cleaner- 16-Ounce or Gum Out
- Carb Rebuild Kit – Buy one prior to taking it apart so that you can replace a torn or worn out gasket (Briggs & Stratton 696146 Carburetor Overhaul Kit). MAKE SURE to double check the engine code / carb model to buy the correct kit!
- Sea Foam Motor Tune Up
– similar to Gum Out but works inside the engine
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
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.
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!
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!
SOURCES / REFERENCES
- Briggs and Stratton – What would prevent an engine from starting
- Briggs and Stratton – Operator’s Manual
- Briggs and Stratton – Parts List Rev. 3
- Generac Wheelhouse 5500 / 5550 – Parts List (PLEASE NOTE: This is for Rev 5)
- Supplemental Generator Data for 87971 Rev. 7
- Disassembly, Cleaning and Repair of Briggs and Stratton Intek Single Cylinder OHV Nikki Carb
- Briggs and Stratton – Illustrated Part’s List
- Briggs and Stratton 10hp Generator Carburetor Repair Video
- Briggs and Stratton – Care and Repair Manual (abbreviated, online PDF version; not too useful
- Briggs and Stratton – Familiarization and Troubleshooting Guide
- Briggs and Stratton – Carburetion Troubleshooting Quick Reference Guide (PDF)