Generators and bad gasoline
Disclaimer… I’m not a generator tech- I do have a rudimentary understanding of them, have had a few introductory classes on them, and service our own Onan Emerald, so…
Today I had (on the end of a list of things to service) an Onan Microquiet 4K which would crank but not start. In trying to start it, I could smell the unmistakable smell of old gasoline.
The gasoline we buy today has a very limited “shelf life”, a couple of months and it gets, for lack of a better term, “funky”. In an automobile, this is no problem, as few people keep a tank of gas for months, but in an RV which might sit for quite a while between uses, this can be a problem. The RV engine is usually not troubled much by bad gas- it might run rough until it is used, but a generator has such a small carburetor that varnish and plugging up is a common occurrence.
The use of a fuel additive such as Stabil is generally recommended. I know of people who swear that it causes harm, but I have used it frequently, and as long as I use it with fresh gasoline, I have never had a problem- and it has saved me hours of cleaning.
But… what if you didn’t use a fuel stabilizer? For this Onan, I did what I often recommend, and disconnected the fuel line at the generator, hooked a short piece of fuel line to it and ran it in to a 5 gallon gas can in which I had a very concentrated mixture of gasoline and Seafoam fuel treatment. Seafoam is a product that I don’t sell, but have used for several years, and it has never let me down. With todays problem generator, it took me several tries to get the treated fuel up in to the carb, then I let it sit for an hour, tried it again and it barely started. I then let it run for a bit, which should get the Seafoam treated fuel filling the carb. I will now let it sit overnight and tomorrow it should start and run like a champ.
The alternative to this would be either rebuilding or replacing the carburetor, which would be hundreds of dollars- yet a full can of Seafoam is under $6 (listed to treat around 20 gallons- I put it in 5 gallons to clean the generator).
Seafoam is also said to be a fuel stabilizer, but I have not ever used it for that, so I cannot comment on its effectiveness in that use, but as a cleaner, it’s great!
Comments
4 Comments on Generators and bad gasoline
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mistergil on
Mon, 22nd Jan 2007 9:36 pm
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Jerry on
Wed, 4th Jul 2007 9:42 pm
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Jim Latour (Generator Jim) on
Fri, 6th Jul 2007 7:36 pm
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RV Mech Tech on
Sat, 12th Apr 2008 8:49 pm
Hello. Came over via a link from Xandros forum. I’m an ex-fulltimer. Ten years on the road pulling a Blazon down south running corps contracts and the like. Anyway this Seafoam sounds like some good stuff, first I’ve ever heard of it and I’ve tore down more than one gen carb thru the years due to gumming up. Currently off the grid and still running my own power setup so this information will be handy to know as I will find a can and keep it available. Thanks for the tip. Gil
As an RVDA Master Certified technician, I can tell you that the best and most sure fire way to store a generator for an extended period is to run it out of gas. All that is required is to disconnect or pinch the fuel line off to the generator, then run the unit until it dies. At this point, remove the fuse from the generator (ususally located near the start switch on the genset). This keeps anyone from trying to crank the genset again until it is ready to be used. If you try to crank the generator even for a short period, the fuel pump will run and fill the carb, which defeats the purpose. Also, I have never heard of fuel stabilizers harming a generator.
I’ve used Sea Foam for a couple of years. I was given an abused 5 year old Honda 1000i that output about 200 watts. Pulled the muffler and poured 4 ounces in and sloshed around. Poured 2 oz in crankcase, 5 oz in gas tank. It killed bugs for a hundred yards around but after an hour or so it produced 650 watts. Changed oil several times and kept Sea Foam in fuel to finish cleaning muffler. Unit now produces 650-700 watts now but burns oil due to worn out rings and valve guides.
Best way to store genset is to drain fuel, blow out carb and fuel lines so ALL fuel is gone. Change oil, remove spark plug, pour in 1 tbsp oil and replace sparkplug. Gently rotate engine until it is just on the power stroke. Both valves are close so no moisture can get in. Tape off starter pull cord so unit cannot be rotated.
As a generator tech I agree that draining the fuel out of a small engine is a good way to store it for the winter but with RV generators moisture will collect in the generator stator and rotor area and cause expenxive damage to the electrical parts- stator insulation breakdown being the most frequent problem – staring the units up once a month at least will dry it out and prevent corrosion of the internal electrical components and putting in fuel stabilizer in the gas will prevent alot of the problems associated with old fuel.I have repaired gensets with this kind of damage with as little as five hours of use that were not started and run and just left sitting.
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