Welcome To My New Generator Repair Page
This website will chronicle my do it yourself generator repair and maintenance.
I own a Generac GP5500 (model 005623-1) which I purchased in August of 2010. It was manufactured in July of 2009 and is a 2009 EPA 49 state legal generator. It's equipped with a 389cc 13hp recoil start engine manufactured by Loncin Industries Ltd., of China.
After the first year of ownership, it became harder to start. I used starting fluid and that helped for a while. It developed an intermittent fuel leak, that could be stopped by tapping on the carb, or by taking the carb off and shaking it to free up the needle valve. By Spring of 2012 it started one last time, ran for 30 seconds, then quit and would not restart.
I took it to my Generac Service Dealer, who cleaned the carburetor an showed me the gunk that collected in the carburetor because of Ethanol E-10 fuel.
Here's What Went Wrong.
The Ethanol E-10 fuel had corroded the float needle valve in the carb.
The needle valve had stuck in the upper position, closing off the fuel flow into the carburetor. Generac does not have internal carb parts available. However the engine and carburetor are clones of the Honda GX390 engine. After searching parts catalogues from Rotary, Stens, and Oregon, I identified the proper float needle and replaced it.
The Huayi Carb Repair page covers how to fix this fuel leak problem.
You are welcome to read through my little web site and learn from my experience.
Important Engine Identification Information
Users of this site should note that Generac is constantly improving and changing their products. Parts and repair procedures I recommend are based on the generator I own. You should always investigate any part or repair I describe and determine if it applicable to your model.
Two basic 389 cc engines have been used for Model GP5500 Generator in the last few years. The engine model with the single center bolt holding on the valve cover is a clone of the Honda GX390 engine, and most internal engine parts can be replaced with Honda parts. This engine is manfactured by Loncin Industries as the G390F. The most curent engine parts diagram for this style of engine is listed as 2009 Production in the Resources section at the top of this page.
The other engine type can be identified by the valve cover being more rectangular in shape and attached to the head with 6 screws. Most internial parts are not interchangeable between the two designs. This engine type is listed as Model 390FA in the Generac Parts Manual, and as the LCPower Model G390F(D)A on Loncin Industries web site. LCPower Technology is Loncin patent technology used to meet EPA Phase III emission regulations (for 2012 and beyond). The most current engine parts diagram for this design, is listed as 2012 Production in the Resources section at the top of the page.If you own a Generac generator, I urge you to always log into their web site, and download the most current parts diagrams for your specific model before attempting any repair. You can always compare the part numbers I list in any repair procedure to the part numbers for your model.
Changes To This Web Site Listed Below. By Date, Newest To Oldest
New: Fall Maintenance Service. Carburetor Cleaning.
Test Results Of Rotary Float Needle.
October 26, 2014.
Fall Services: drain fuel tank, remove air filter assembly and clean, clean fuel sediment cup, change oil, dissemble carburetor and replace float needle. replace air filter, dispose of old fuel in automobile, recycle engine oil, add new fuel to generator and test run. Total time to preform the fall service was 4 hours, including shopping trip to hardware store.
Installed the following parts: Stens Float Needle #525-554, Generac carburetor gasket #0G9916, Generac carburetor gasket #0G84420156 (quantity 2), Rotary air filter #12801. Danco o-ring. Mobil-1 10w30 oil.
I recently did a fall tune up of my generator. This included the disassembly of the Huayi carburetor to see how the Rotary brand of float needle was holding up. I consider myself lucky as once again, we did not have a summer storm that required use of the generator. Sooner or later my luck is going to change. For the last two years I have only needed to exercise the generator, not use it durning a power outage. I did not replace the spark plug as it was not necessary (not enough engine run time on plug since it was last replaced). I also did not adjust the valves. While Generac recommends valve adjustment every 50 hours, Locin recommends this at 300 hours run time. The engine starts up on one pull, before and after this service.
It had been 27 months since I had put in a Rotary replacement float needle and spring (part # 10475), and it was time to see how it held up.
I dissembled the carb and found that the inside was clean with no trash or corrosion. The Rotary brand float needle had no corrosion and looked brand new. All of the internal parts were clean. I installed a new Stens brand of float needle and will report later on how this one holds up. When cleaning this carb, I noticed the float shaft is not magnetic (I was using a magnetic dish to hold all the parts). It a bright finish, so its most likely an aluminum wire with a chrome plating for corrosion resistance. Just dont use lose this part when you service your carb.
My examination of the carb showed the 2 o-rings that are used on the bowl nut were cracked with age. Loncin #380840841-T560, large o-ring and Loncin #380840519-T560, small o-ring. These parts are not available in the US.The local hardware store has some Danco plumbing o-rings and I was able to find one of the two that fit reasonably well. These o-rings are not suitable for use with gasoline, so I will have to replace them again. The large o-ring fits between the carburetor bowl and bowl nut, while the smaller o-ring fits on the shoulder of the Anti-Afterfire Solenoid and goes into a recess in the bowl nut face. Both are required to keep fuel from leaking. I assume mine had premature wear because the carb had been taken apart multiple times as I learned how to repair it. I have obtained a metric o-ring kit from Harbor Freight which I will use to fit new o-rings in the spring. The carb is not leaking at this time.
The rest of the fall maintenance went off with out a hitch. Carburetor mounting gaskets were replace because they had become brittle. Installed a new one piece air filter to replce the two piece OEM filter. Fuel lines are in good shape, no trash in the fuel filter. Inside of fuel tank was free from rust or corrosion. Their was no trash in the filter screen on the fuel shut off.
Changed the oil (I use Mobil-1 10w30) with the Drainzit Oil Drain Hose for the first time. I put #HON1012 on the generator two years ago. All I had to do was put some bricks under the wheels to elevate the generator. I removed the cap and allowed the oil to drain into a empty 2 liter soda bottle. This was much easer and cleaner than draining into a pan. When not in use, I keep the hose strapped to the inside of the frame with some velcro. No chance of damage as its protected by the frame member. No spills, no mess, the Dranzit oil drain hose is the best $20 I have spent in a long time.
Generator was put back together and run for one hour with a load. No problems or leaks. Engine rpm was stable after about 1 minute of warm up. Ran engine until tank was empty. Removed carb drain screw, and pulled rope several times. Some fuel dribbled out. Took a soft rag and wiped it down. Put it away. Now I have to get some winter fuel and Ill be ready for the winter Northeaster.
If you need to replace the float needle in your generator, the Rotary #10475 float needle is an acceptable substitute for the Honda needle in this generator.
Updated: Engine Diagrams for 389cc Generator Engines.
February 8, 2014.
Generac changed their web pages, so I updated the links to the two different Type G19, engine parts diagrams. Now when you click on the link above, it will take you to the main support page for a generator with that type of engine. From their you can download the most current parts manual.
New: Carburetor Bowl Gaskets Available.
December 22, 2013.
Individual Bowl Gaskets are available from small engine dealers stocking the following parts.
Stens 485-974:
fits Honda GX240 through GX390 and Chinese clone engines.
Stens 485-970:
fits Honda GX110 through GX200 and GXV120 through GXV160 and Chinese clone engines. See the Water Cannon parts kit for more carburetor o-rings.
I have updated the Carburetor Repair page with those links.
New: Float Needle Corrosion Picture.
September 03, 2013.
A big thanks goes out to Bill Cicio In NY, USA, for an excellent picture of how a float needle looks when corroded. He has been working on an Generac GP7500E that has the same fuel leak problem as my GP-5500. View His Picture Here.
The needle has a bright finish with a light grey synthetic tip . The black ring you see around the tip is where it seats against the fuel inlet in the carburetor bowl. This black ring is normal. Notice the corrosion on the right hand side of the picture.
New: Spring Start Up & Fuel Tank Capacity.
June 20, 2013.
Spring Services: drain fuel tank, remove air filter assembly and clean, replace fuel line and filter, clean fuel sediment cup, clean and reinstall air filter assembly, dispose of old fuel in automobile, add new fuel to generator and test run. Total time to preform the spring service was 3 hours. I did oil change and spark plug replacement last fall.
I recently did a spring start up of my generator. Durning the check, I drained the old fuel from the tank, and checked the fuel capacity against the specifications. The owners manual for my GP 5500 states that it's a 6.6 Gallons U.S. capacity. When I went to refuel the generator, it took only 5 Gallons U.S. to fill it up to 1/4 inch below top of the filter cup. If this unit has a 6.6 gal capacity, then it's what called Water Capacity. What that means, the tank will hold 6.6 gal when full up to the max with no air trapped in it. It does not mean you have have 6.6 gal of usable fuel capacity. Fill it with more that 5 gallons, and its prone to leakage from under the fuel cap. Please make a note of this.
Durning the spring check I found that the original fuel line was split along it's length at the fuel shut off valve. The split was about 1/2 inch long. The pressure from the barb stretching the fuel line in this place had caused it to split. It was the original line and was three years old. I replaced it with Tygon fuel line and a Visu Fulter (part #FF901C). Both were made USA. Also I replaced the original fuel clamp with Stens clamps. They were a tight fit. Had to put them on the hose barb, and then push the fuel line on while using pliers to hold the clamp open. The original fuel line was 10 1/2 inch long including the filter. I placed the filter so it's just above the top of the air filter. The air filter had to be removed to replace the fuel line. The new fuel line clears the governor rod with plenty of room.
After repairs I ran the generator for 30 minutes, checking for leaks and to make sure the choice of fuel filter did not starve the engine for fuel. Worked fine with no problems.
New: Dominion Power Generator Connection.
February 27, 2013.
Dominion Power sold the PSP Products TRANSCONNECT Transfer Kit under the name Generator Connection Hub, until June of 2012. This kit connects a portable generator to your meter base. Using this product I was able to avoid the cost of interior renovation and plaster/painting repairs to my home as my electrical panel is inside the house, not in the garage or outside.
While Dominion Power has discontinued selling this product and removed all reference to the product from their web site, I have put the manufactures information on the Tools & Accessories page. If you need service for the Dominion Generator Connection Hub, contact PSP products. You can also contact the Electrical Contractor who installed the hub for you.Also posted on the same page is information about a competing products, the GenerLink transfer switch, circuit breaker interlocks and converting a portable generator to run on Propane or Natural Gas in addition to Gasoline.
New: Generator Grounding and Neutral Bonding.
February 25, 2013.
Information on the difference between a Floating Neutral, Bonded Neutral and grounding.
Problems using generators
with full panel GFI protection and transfer switches.
Update: Manuals Page.
February 24, 2013.
New links to Honeywell Portable Generators sold by Northshore Power Systems LLC. (company out of business late 2010), including Service Manuals and Service Bulletins. Honeywell branded generators whose model number begins with HW were sold by Northshore. All others sold and serviced by Generac.
If you are looking for repair information on Chinese made generators, I suggest that you download this new repair information before it disappears from the web.
Other Service Manuals Posted This update: VAISI Generator Service Manuals, Suburau Robin Service Manuals & Owners Manuals, DeVilbiss Generator Service Manuals & Wiring Diagrams.
Check the Manuals page often. I make updates regularly.
NEW: Manuals Page Posted.
February 02, 2013.
Owners manuals, service manuals, small engine manuals, generator manuals, and any other manuals I found while building this site. Click on the Service Manuals Link on the right.
NEW: CPCS Announces Recall Of Champion Generator Due To Risk Of Fire Caused By Fuel Leak.
November 15, 2012.
NEW: Tools and Accessories Information Posted.
November 14, 2012.
Small engine service tools, generator plugs and connectors, fuel cans and pumps. With links to Amazon so you can see the pictures of the item, and its review.
NEW: Carburetor Repair Parts Information Posted.
October 20, 2012.
A new and expanded listing of carburetor parts, tools and service manuals posted.
NEW: Generac GP5500 Fuel Leak Fix Posted.
October 1, 2012.
My generator uses a Generac Branded 389cc (Type 188F made in China) Engine which is a clone of the Honda GX390 engine with different carburetors selected for each application. This size engine is used on many generators, trash pumps and construction equipment.
My first article is now ready. Click on the link for Huayi Carb Repair. It covers all you need to know to solve this common fuel leaking problem.
The Info links on the right have more carburetor repair information, including service movies on how to clean a Honda GX390 carb. The Chinese made carbs are the same design. See the Carburetor Repair page for more details about carb repair.
With my carburetor problem solved, I have started collecting part compatibility information about these Chinese made engines. This information will be posted shortly.
Future articles will cover the new Drainzit oil change accessory I am about to install, Proper Fuel Storage For Hurricane Preparedness, How To Store Your Generator: what the manufacturers forget to tell you, and others.
Check back often. I hope you find this information useful. Contact me if you have any questions, suggestions or information to share.