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Reviews Categories | Emergency/Portable Power: generators, solar, wind, thermal, etc | Generac 4000EXL 4KW Generator Help

Reviews Summary for Generac 4000EXL 4KW Generator
Generac 4000EXL 4KW Generator Reviews: 7 Average rating: 4.1/5 MSRP: $729
Description: 4KW (6.6KW surge) 120/240VAC Generator
Product is in production.
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K6BRN Rating: 4/5 Feb 28, 2016 21:26 Send this review to a friend
Small for its output...  Time owned: more than 12 months
Have had this generator for more than 15 years and used it mainly for nearly monthly power outages of 1-16 hours. Unit has been reliable but noisy, as all open-frame gas generators are. Replaced it with a very quiet Honda EU6500is about 5 years ago - needed a bit more power to handle my XYL's home office and wanted to quiet the racket - but could not really let go of this old gem. Recently filled it with gas and tested it, only to find low voltage output (105 VAC RMS). AVR unit is adjustable via a potentiometer accessible through a hole in side of case, so reset voltage to 120 VAC RMS and unit works like new. Potentiometer seems cheesy and prone to vibration driven drift, though. Agree with previous review gas comments - gas generators MUST be stored with empty tanks and carburetor bowls, or they will gum up and begin to surge. My unit has a pressurized oil system, automotive oil filter and overhead cam 7.8 HP Generac engine that seems very durable and starts easily. No electric start on mine (4000XL)
W6LBV Rating: 5/5 Sep 14, 2014 09:58 Send this review to a friend
Fuel Lessons From My Generator  Time owned: more than 12 months
This is a follow-up to my 2005 review of the Generac 4000(E)XL, a product which I still own and use. It also contains recommendations for dealing with a persistent fuel problem that affects such generators.

Since 2005 I have had some problems with the overall auxiliary electrical power generation process, but they have not been due to the Generac. Rather they have been caused by the fuel used for the generator and the changes that have occurred to that fuel. The fact that I use the generator only during emergencies, which occur infrequently and after long periods of fuel storage, promotes these problems.

During the last ten or fifteen years the legally-mandated addition of ethanol to pure gasoline, yielding “gasohol,” has proved to be “one small step for air pollution, one giant leap BACKWARDS for consumers.” My generator problems have resulted from the unavoidable use of chemically-unstable gasohol, and these problems have been ongoing.

I have the educational/technical background to understand these problems in some detail, and they are not a mystery. Gasoline itself is unstable during long periods of storage (it spontaneously but slowly forms polymeric varnishes and “gums,” among other problems) and the addition of ethanol to gasoline hugely increases its stability problems.

Pure ethanol (grain alcohol, made industrially primarily from corn-based sugar) has a natural and unstoppable tendency to attract and to absorb water, often from the air space above the gasohol fuel. (The most stable ethanol/water mixture is 95% alcohol/5% water). Once an ethanol/water mixture forms within gasohol, new possibilities for both decomposition of the fuel and corrosion are created, and the speed of fuel decomposition increases. It is my fight against these gasohol problems that I describe here.

Separately from the gasohol problem, over time the original 4000(E)XL fuel tank-to-carburetor rubber hose decomposed. (Rubber fuel hoses should be routinely replaced.) The rubber decomposition products clogged the original carb, which could not be successfully cleaned out. That required replacement of the carb with a brand new one.

After the carb swap I resumed storing the generator with a traditional gasohol + “stabilizer product” mixture contained in its fuel tank. A year and several fuel drain/refill cycles after replacing the carb, the float valve in the new carb showed signs of again being gummed up and inoperable, and the generator would not start. I removed the new carb, disassembled it, and cleaned the parts extensively with carburetor cleaner, removing a wad of newly-formed brown gum. Clearly the traditional fuel stabilizer products had not been effective on gasohol. After the carb clean out and re-installation, the 4000(E)XL again started and ran reliably with fresh fuel.

These are the procedures I am now following to avoid gasohol storage problems with the generator. These preventive measures can be applicable to all gasoline-powered small engines that must use gasohol.

1. While the generator is still running, I first shut off the fuel tank outlet valve and let the generator continue to run until it stalls from fuel starvation.

2. I drain all remaining fuel from the generator tank into an approved storage container and blow the remaining gasoline vapor out of the tank with compressed air. The tank then remains completely empty and sealed during storage.

3. IMPORTANT: I then loosen the carburetor bowl bottom drain bolt and let any fuel remaining in the carb drain to completion into a small jar. Then I re-tighten the bolt.

4. For future use in emergencies I externally store small amounts of the highest octane-rating gasohol that I can buy, in approved containers. I add a stabilizer to the stored fuel; a newly- announced product line of stabilizers now claims to handle “the alcohol problem.” However, I have no results yet to report for this product. OPTIONAL: after a few months of storage the unused (aged) fuel can be poured into a car’s gas tank, if desired. There it mixes with a larger quantity of fresh fuel already on-board and burns normally. New, stabilized gasohol then replaces the old fuel in the storage containers.

5. At the start of the next emergency the externally stored fuel is poured into the generator’s tank just prior to use. Thus the generator is stored “bone dry” between uses.

For the particular carburetor used on the 4000(E)XL, “rebuild” kits are no longer available, but new carbs are offered for sale on the Web. The carburetor is very simple to service for cleaning and replacement. Anyone who has done any kind of automotive engine work should easily be able to do the maintenance on this miniature carb. CAUTION: always do carb servicing work only in extremely well ventilated, flame- and spark-free areas!

Propane and natural gas fuel conversion kits are available for the 4000(E)XL but are expensive.

It is a good idea to exercise the generator at least once a year (more is better), in order to keep the capacitors on the electronic control board in good operating condition. Run the generator for a minimum of ten minutes to do this (more is better). Change the crankcase oil and filter after a few years of occasional use, and check the air filter.

I am still very happy with this generator despite the fuel problems, and I certainly would buy a Generac replacement if a new one were ever needed.

N0GV Rating: 5/5 Oct 21, 2005 12:17 Send this review to a friend
Good Unit  Time owned: months
I have an earlier and larger unit -- the 5500 XL --- It has been run well in excess of 400 hours and has proven reliable, rugged and dependable. There are many brands of generators out there and some are better than others. Some are "quiet" and very expensive, some are cheap and flimsy and shake themselves apart in a few hours and some are just plain rip-offs.

This generator is now over a decade old, still runs great (just checked it out before Wilma gets here) ran about 100 hours after Katrina and I would buy another Generac product in a heartbeat!

As for Oil filter and so on not in the box.... Reading the instructions is always a good idea before buying. ;-) Filters are available at the Home Depot (seen plenty of them even when there are no more generators available ;-) ).

Just remember -- a 15 kW Genset with a surge rating of 25 kW will likely start the central air unit but it will gobble ~25 gallons of gas per hour! The 5500 slurps about 1/2 a gallon per hour depending on the load....

Grover Larkins
KD4ULW Rating: 5/5 Jul 29, 2005 09:45 Send this review to a friend
Works Great!  Time owned: 0 to 3 months
After reading the forums and comparing the different pro’s and con’s, I decided on the 4000EXL. There are higher wattage units, but I wanted a cleaner waveform system, and this one has a built-in regulator which provides a more stable platform for sensitive electronics.

Just got to test the system due to a 90 minute outage on a clear day!! No problems encountered at all with the gen.

Not much more to add than others have posted, but this generator came with an oil filter and oil, so I guess that is a recent addition from the non-filtered ones. You can now run ‘out of the box’.

Also, with the idle system on and not under any load, the unit will be show less voltage until there is a load present… then the unit automatically revs up and output is normal.

Plus, take the time to install a manual switch and keep yourself and others safe, sure makes hooking up the house a lot easier!!!
BILLYBOY Rating: 5/5 Oct 2, 2004 05:59 Send this review to a friend
The one to buy  Time owned: 0 to 3 months
I've been a design engineer for 31 years and all that time I have worked for a company that makes electrical generation equipment. I live in central Florida very near the intersection of Hurricanes Charlie, Frances, and Jeanne. I purchased this unit right after Charlie (8-13-04) and it was the only one I could find available anywhere. Since then, I have looked at a lot of other units of all sizes and makes. I used this generator after Frances and after Jeanne. Here is my conclusion: If I had been given all the time in the world to shop for a back-up generator for my home, this is the one I would have purchased anyway. The combination of continuous power rating, surge capacity, and demonstrated fuel efficiency of this unit,for this price is unmatched. My hurricane power kit now includes this generator, a 6000 BTU Maytag window air conditioner, two 50 foot 12 guage wire extension cords, oil, $3 oil filter (same as on my 95 corolla), and a bottle of fuel stabilizer. The reason you can get all the power of the generator thru those two extension cords is that each socket of the 120V duplex outlet is protected by an 18 AMP breaker which would allow 120 X 18 X 2 = 4320 watts. These breakers don't pop during short term surges when the AC or fridge are starting up. Buy this one, your wife can start it easily while you are at work.
THINK7 Rating: 0/5 Sep 29, 2004 16:44 Send this review to a friend
Save Your Money - Buy Something Real  Time owned: 0 to 3 months
I don't share the other reviewer's opinion on this piece of junk. Right out of the box the DC voltage was in the 8-9 range. Had it for service twice already with less than 30 hours on it. Totally responsible for blowing our 1hp well pump when it was the only load on the genset.
Output intermittently crashes under load.

Difficult to procure oil filter that you don't even know you need until you open the box (which by then with a hurricane on the way was low on my list of essentials). This company doesn't impress me nor does Home Depot for selling this crap can.

You would think (the "you" in this case is me) that a company selling literally tens of thousands of generators to Florida consumers in the last few weeks would have the common courtesy, the decency and the foresight to man the phones on the weekend that a hurricane was blowing through - on the off chance that a few of those tens of thousands of customers might have some questions. Not these self centered dimwits.

I am going whole house genset (probably SDMO 60KVH diesel) and strongly suggest that anyone who can afford more than this Generac/Guardian junk buy a real genset that will last.

KG5PT Rating: 5/5 Jan 24, 2004 17:47 Send this review to a friend
Unbeatable Value!  Time owned: more than 12 months
Lots of features for the money – Electric start is almost unheard of in this size class, let alone in a model that costs less than $750. The engine is very high-quality: Aluminum overhead-valve, with full-pressure lubrication, automatic low oil pressure shutoff, and an automotive-style spin-on replaceable oil filter. Interestingly, this "Nagano" engine is actually designed and built by Generac, unlike most of the other brands that use Honda or Briggs engines. (The Generac Portable Power division that produces this model was recently bought by Briggs & Stratton, so parts and service now also available from B&S dealers.).

The alternator produces a clean waveform and has very good voltage regulation. The surge capacity is 6.6 KW - pretty amazing for a 4 KW model. The 4.5 gallon fuel tank is claimed to run the generator for 14 hours at half of rated power (haven't verified that, but it seems very frugual).

Up to 10 amps of 12VDC power is also available for charging an external battery; the internal battery is charged via a separate circuit. Both 120VAC and 240VAC outlets are included – Unlike many cheaper models, the 120VAC side is fully capable of supplying the generator's full 4KW rated power through a single circuit.

The generator includes some nice no-cost extras – Wheel kit with pneumatic tires, an AC-powered battery trickle-charger for the 10AH Gell-Cell starting battery (also included), twist-lock plugs that mate with the 30 amp 120VAC and 20 amp 120/240VAC outlets, a battery charger cable with alligator clips, and a small package of fuel stabilizer. I get the feeling that Generac did'nt cut costs with this model, in spite of the fact that it's priced hundreds less than comparable products.

About the only down side of this model is the noise level, which I'd describe as in the "medium" category – not nearly as noisy as the entry-level cheapies, but not nearly as quiet as some of the high-end Hondas, either. The muffler is decent-sized, but the lack of engine shouding or noise insulation materials means that there is still plenty of mechanical and fan noise.

I've put about 160 hours on mine so far, with absolutely no problems. It starts on the first couple of engine revolutions, as long as you rememer to flip the choke first to prime it on cold mornings. Generac recommends oil changes every 50 hours, which I consider to be excessive. I'm running synthetic 10W-30 in mine, and will be changing the oil every 100 hours. Oil consumption is nil. The pricey $8 "Generac" oil filter cross-references to much cheaper automotive filters – just ask for a filter for a 1988-2002 Toyota Corolla/Celica 1.5/1.8L (Fram PH4967 or equivalent).

Note that this exact Generac-branded model is only currently sold at Home Depot ($729), although Sears also sells a Craftsman-branded similar model without electric start.

If you're looking for a higher-power generator, Generac also makes the 7000EXL, which is a 7KW version with a larger version of the "Nagano" engine and essentially identical features. Hard to go wrong with either model, IMO.

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