Ajust the float in your carb (bend the brass tab in that the top of the needle valve touches)and clean this needle valve. the bowl can be removed with a 7/16 box wrench on the bottom brass nut that is also a needle jet (clean this jet ,some models it is just a jet, others it is ajustable and needs to be 1 turn out to start then ajust wile running hot untill it stops surging) the problem is not allowing enough fuel to fill the float bowl

My answer:

Not knowing your exact model #, and knowing only that you say it is 3 years old - 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. Coleman does not 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 are 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?

Since I take it that it has been running good up to now - i have a few ??'s as to how you have been running it recently. What do you mean when you say - "First time being used." Are you talking about the 1st time this year being used - or what?

Since 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 beforehand - running it the last time out - unless it was ran low on oil - in which case it should have a LOW OIL cutoff switch mounted in the lower engine case close to the CHECK OIL port.

If the LOW OIL switch is working properly and adjusted properly then you shouldn't be getting any engine cutout - that is unless either this OIL LEVEL float switch is mis-adjusted, or else the OIL LEVEL is indeed low. (ie: switch is mechanically set too low, as then when the oil level is indeed at it's proper level the switch would be already shorting out to ground) (See your operators manual for proper setting)

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

A way to check for proper operation of the LOW OIL SWITCH is to temporarily disconnect the (usually) BLACK wire from the LOW OIL switch when the engine starts to cut out. If the stalling out problem goes away completely then the LOW OIL switch is either mis-adjusted, or else it is going bad from vibration. Also check this if it's not starting - as it may already be shorting out the Maintenance-free Magnetron® electronic ignition, and thus sending NO SPARK to the SPARK PLUG. Pulling the SPARK PLUG out and grounding it properly on the engine head or any grounded metal surface will affirm this. (Again see your operators manual for proper adjustment and/or check out procedure)

Electronically this LOW OIL switch should be the only thing that would protect the engine from damage should the oil level fall below recommended level. Other then that it may have an electronic REV LIMITER if it's a bigger and more expensive model, but usually not.

I doubt the Maintenance-free Magnetron® electronic ignition is at fault, but could be weak and going bad. Always a possibility, but I would 1st rule out everything else first.

Since the/your Genset runs for only 3 secs 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 air/fuel mixture Jet Adjustment Screws.

Let me know if you should need that adjustment procedure 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 does sound like it's starving for gas unless it's building up a (vacuum) or vapor lock in the gas tank.

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 Electronics/electrical/fuel standpoint engine wise - there is only one other thing left Genset wise.

Beings your Genset is said to be 3 years old, and it just indeed might 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 most likely is 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,

Frank

Simple... if the engine is fireing, the problem is the carborator and/or the sparkplug. Take the the carborator off then take it apart and give it a really good cleaning... if it has a diafram...replace it and if it has a bowl...seal it really well.