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Running problems, with a UST gg5500 generator, not previously covered.

After initial start, it will run fine until it warms up. Then, it acts as though it runs out of fuel, starts to shut down, backfires and starts running fine. This happens every 3-5 min. Unit is approx. 3yrs. old.

Posted by Anonymous on


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  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

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Posted on Jan 02, 2017

  • 72 Answers

SOURCE: Generator Starts but won't continue running/dumpimg fresh fuel into filter

My answer:

Not knowing your exact model # or how old it is, and knowing only what you said above - TOTAL RUN HOURS unknown as well? - I can only give you several possibilities of what the problem might be - even though I don't know the exact model # and which engine you have on the Genset. Porter Cable as well as Coleman and others do not themselves mfr much of anything today, but like with many USA companies out there today it does private label out to a lot of mfg vendors (mostly in China btw), and the Genset gas engines are numerous. From Briggs & Stratton to Honda to Subaru and so forth...

I also don't know what normal LOAD you were putting on your Genset there, or have been putting on it previously, or at what RPM you are normally running the engine at - as to half throttle or full throttle setting?? I take it that it's a Briggs & Stratton 4-stroke single cyl, or is it a Honda 4-stroke single/twin cyl engine?

Any Genset that is going to be put into storage for that long a period of time I would first and foremost recommend running the Carb Bowl dry first by running the Genset at FULL speed, and while running turning off the gas until it dies. Thus removing as much gas from the Carb Float Bowl as possible!

Most people do not do this and forget about that small amount of stale gas in the Float Bowl, and that is what causes VARNISH in the Carb Bowl faster then anything else.

Just putting a gas preservative in the gas tank doesn't solve the VARNISH problem because that never gets down to the Carb to begin with if the gas line shut-off valve is closed before the preservative gets down there.

If the Float decides to stick while in storage, and then it's brought out to fire up naturally the gas will flood out the Carb and probably the Air Filter Box as well.

It's always better to store the Genset DRY! I know I do and I have NO problems at all with stale gas, etc.

Since all Gensets need to be run a minimum of 10 minutes every 30 days (every 1 month religiously), or whatever your owners manual recommends - if you haven't been doing this, or don't run the gas out of the Float Bowl before shutting the Genset down after each use - then most likely the Carb is gummy or possibly has dirty gas in the bowl and is the problem.

I seriously doubt you did any damage to the engine by the recent gas over-run and flooding.

You might try and tap carefully on the bottom or side of the Float Bowl with a hard rubber hammer first to try and see if you can dislodge the stuck Float inside. If there is a WIRE at the bottom of the Float Bowl on your model - DO NOT HIT THAT GAS SHUT-OFF SOLENOID WITH THE RUBBER HAMMER - as you will do damage to it! If this dislodges the stuck Float then your problem is solved!

You may still want to run a bottle of Carb Cleaner in the tank just in case to clean out any residual buildup in the Float Bowl, etc. If it runs fine then No Problem.

First and foremost always check your OIL LEVEL and make sure you have changed it out according to your owners manual!!!

If your Genset still runs sporadically for only a short time and then starts to cut out I would look more for like a fuel vapor lock (partially closed or clogged gas cap vent), a possible dirty fuel filter, possible water moisture in the gas tank or in the Carb bowl, possibly dirty Carb in general along with it's dirty Float Bowl, Float Pin, Float and Needle Valve, and any Adjustment Screws that go Into the Carb Body.

It's hard to say unless the Carb first is broken down, checked for proper Float action setting, and/or cleaned out accordingly if dirt is indeed present in the bottom of the Float Bowl.

If all looks good there Carb Bowl wise then you will next need to check the FLOAT adjustment itself to make sure you aren't flooding the Bowl. Your Operators/Service Manual should have that adjustment there. If not let me know and I'll post it for you. Also the air/fuel mixture Jet Adjustment Screws will need to checked as well.

Let me know if you should need that adjustment procedure as well after you first check out everything else I stated above?

That covers everything from a fuel standpoint.

Again - You do know that all Gensets should be started and run for at least 10 mins every 30 days - right? If you didn't know this - now you do! Every good operators manual should state this.

It just doesn't sound like it's starving for gas - that's for sure!

The gas tank fuel line does have an in-line fuel filter correct? If it doesn't you definitely need to add one for dirt protection!!

Having covered everything from an fuel standpoint engine wise - there is only one other thing left Genset wise.

Beings your Genset there might just have some high RUNTIME HOURS on it - it just could very possibly be what sounds like to me (and I personally HAVE SEEN this happen myself firsthand) that the generator brushes are nearly shot - as in almost worn out. They may be getting too too hot - as from excessive current draw at point of contact, and thus the generator sensing circuitry itself is doing an electrical CUTOUT!!

An added protective Genset circuit feature in that the generator itself may indeed be linked to the engine as a type of REV LIMITER or CUTOUT on the Maintenance-free Magnetron® electronic ignition. Again - your operators or service manual should have a pretty good troubleshooting section in it unless you don't have that anymore or never got one if you bought it used to begin with.

If you unscrew & remove the Generator brushes, and they are indeed below the recommended length (or worse case they are indeed totally worn down) then that too most likely could be your problem right there.

If you choose to replace the old brushes with new ones yourself - be very careful when seating the new ones - as to their insertion and cap retainer tightening. Never over-tighten those black plastic-like brush retainer screw caps - for if you break one (hard to get immediate replacements is why), or fracture one it could cause the Genset to fail under LOAD, and that very well could do some severe damage to the generator part itself. Take your time doing it, and be patient!!

It has to be one of the scenarios listed above, as I've covered every possible cause short of a broken wire somewhere - which in that case you will have to schematic trace and Ohm out wire to wire contacts. This being the least likely scenario from experience.

If you indeed find the Float Bowl assy to be the cause of dirt contamination or varnish build-up clogging the Carb, and you need a walk-through of taking it apart, cleaning it out, and then re-assembling it again - as well as re-adjusting the fuel mixture Adjustment Screws - just give me a shout here, and I'll walk you through it step by step.

Please post me a reply as to the found problem there, and the resolve to it by following my recommendations above. Also please rate my troubleshooting fix as well.

Keep me posted and I'll follow up as well.

Best regards,




People experiencing starting issues often are not using fuel stabilizer or not changing their oil. I myself or any good repair shop will first pull the oil out, and most times we'll will find that it has metallic build up common from any small gas engine that has been neglected.

Posted on Sep 03, 2008

  • 14 Answers

SOURCE: Generator only runs in choke position

leak at carburator gasket

Posted on Jan 03, 2009

  • 1 Answer

SOURCE: 5500 gas generator

I had the same problem. My problem was the oil sensor. Unplug the oil sensor wite and see if it starts. If it does the order a new one, they are about 12 bucks

Posted on Jan 11, 2009

  • 32 Answers

SOURCE: Backfire Tecumseh Generator

To maybe convert your Flamethrower back to a generator, Make sure the fuel line is a good quality thick rubber material (like OEM )since it passes through the engine,HEAT is a issue, if it has been modified to steel, or it's thin rubber, it will overheat the fuel on its way to the carb and cause backfires after the engine warms up , ( vaporizing gas and pressure bypassing the jets flooding the engine) I use 1/4 inch Goodyear sold at Autozone , one of very few name brand quality parts you can get there. The other possible cause is carbon deposits built up on the leading edge of the valve not allowing the valve to close all the way, just clean the valve, it is caused by too lean or rich carb setting or clogged jets, if it is a newer style carb with a pink main jet then debris in this area will always cause backfire, check and make sure the old tiny O-ring on this jet is not still in the bottom of the shaft, people forget to pull them out all the time or give up trying to pull them out, I use a paper clip and bend the end 1/8 of a inch @ 90 degrees to fish hook it out of there, CLEAN THE SHAFT with carb cleaner and a Q-tip.... A Tecumseh engine will always backfire if the carb or airflow is not perfect and sealed tight !!!!!! it looks simple to rebuild the carb but you must take your time and look close, clean it very well, make sure the jet is SEATED properly and all tiny holes are clean, use guitar string not torch head cleaners as they will enlarge the holes and make your carb run rich.

Posted on Feb 05, 2009

  • 1066 Answers

SOURCE: runs great until hot.

put some fuel cleaner in the fuel tank and replace the spark plugs.

Posted on Mar 22, 2009

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