Question about Watts Onan Portable Generator - 4000 , Model# 5500

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Will 10% ethanol in gas hurt generator? Mine seems to be idling a little rough these days.

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I wouldn't say the ethanol is the problem, but perhaps the brand of gasoline. I can tell you that many cars including my own run crappy on certain gasolines (even though all gasoline contains 10% ethanol), when they get older. For example I get horrible gas mileage on Exxon gas, while I get wonderful mileage on Shell or BP gas. Experiment with that a little and if there is no improvement you (or if your not sure how a shop that deals with generators can do it for you) can adjust the idle and check any filters that may be one the generator.

Posted on Jul 07, 2010


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Honda generator EB3500 wont idle when put into auto idle, it will basicly want to stop

Carburetor is probably gummed up. Try running some "Sea Foam" in your gas, run it until the mix is in the carb and then shut it off and let it sit. I had to let a snowblower sit a week until it dissolved all the gum. If your using gas with Ethanol, this is a common problem. Try finding a station that sells gas without Ethanol or use Sea Foam to keep the Ethanol from breaking down. (It can break down in as little as 30 days).

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Honda generator (eb5000) will not idle steadily

use premium non-ethanol fuel(shell,BPS etc).Many stations to the west & north (,Hustisford & many other town's PREMIUM are non-ethanol) and add some sea foam to it. that ethanol is junk. If not used in 30 days toss it. nothin' but trouble.

Jun 25, 2012 | Electrical Supplies

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Generator trouble starting and running rough

ok simple things first, new spark plug, fresh gas, a decent dose of fuel cleaner a bottle doses 12 gallons so say if 3 gallons gas use 1/4 bottle (yes double dose wont hurt) , air filter, try running this first and see if it picks up over time, the methanol gas really crude's up small engines and the cleaner will hopefully clear it up, use fuel stabilizer with ethanol protection and dont let tank sit empty always full to keep moisture to lowest level. if this doesnt work then likely carb is fouled and needs rebuild

Jun 03, 2012 | Hammering

1 Answer

My pro user g5000 generator wonts start after being stood for 6 months any ideas

Hello John, Your gas more than likely has gone bad. If you have spark and good compression and it won't start then chances are the gas has gone bad. Today's gas contains about 10% ethanol, which is absolutely terrible for small engines. Gas with ethanol has a max shelf life of about 90 days under perfect conditions. A month or less is more realistic. Here is the problem, ethanol absorbs water and sits at the bottom of the tank in the generator. If You have a 5 gallon tank With 10% ethanol then 10% times 5 gallons equals half a gallon of water saturated ethanol sitting at the bottom of the tank, I don't care what kind or how good an engine it is, it won't run on water saturated alcohol. Here is a great video explaining it. So what I would suggest is to drain the tank and the carburetor bowl of all the old gas. Replace the bowl and check for leaks. While everything is empty I would suggest that you replace the fuel line with a Tygon line. Tygon is resistant to ethanol. I would also ad a see through inline fuel filter and a new spark plug. After this is all done, put in a small amount of gas, less then a half gallon and see if she fires up. If it fires up right away you should be all good to go. Let the generator run until it's completely empty. And store it empty. Here are some problems and solutions that I have for gas with ethanol. I live in Savannah Georgia and the high humidity during the summer can ruin the gas in my lawn tractor in less than 2 weeks due to water saturation. The tractor is almost impossible to start and runs terribly until the remaining gas is used up. I have stopped filling the tank completely and I use just enough gas to cut the lawn then I store the tractor almost empty. I also use gas cans made by a company called Blitz. These containers are pretty much airtight and do not allow the ethanol to absorb water. This has made a tremendous difference in engine performance. Another thing that you can do is to check out this website If you are lucky , you might have a gas station that sells gasoline without any ethanol added. This type of gas has a much longer shelf life and if a product like Stabil is added, you might get over a year of safe storage of gas for your generator. Municipal airports have banned ethanol in aviation gas and so have most marina's. It might cost a little more but it sure is worth it when the lights go out. If you can't find pure gas then I suggest you store gas in the Blitz containers for about 3 to 4 months. If you don't need to use the generator then use the gas in your car and refill the Blitz tanks again. Better safe than sorry. I hope this helps and if it does would you please be so kind and give me a positive rating for my solution. Good luck and thank you, Michael Burke.

Jan 04, 2012 | Coleman Electrical Supplies

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I have an old makita g2700 generator with a robin ey25 engine.i need to change the oil.what grade of oil is recommended please

Hi Tim,
That engine's original production started out in 1987 by Teledyne and then taken over by Robin Subaru. Replacing your oil depends upon your climate, here's a list Below 14 degrees F 10w30 14-68 degrees F SAE #20 68-104 degrees F SAE #30A complete fill requires 28.7 OZ of oil according to the service manual.If the engine is burning a lot of, oil I would suggest that you jump up a rating on the oil. For example if you are in Florida and it's 95 degrees outside I would useSAE #40. If the engine is still within its tolerance and not consuming oil I would stick with the factory recommendations. On a further note,This is a fairly old generator and was designed to run on straight gas, NO ETHANOL!!!! Today's gas has at least 10% and it will wreak havoc on your fuel system. Ethanol will absorb water from the moisture in the air, It bonds with the water and sinks to the bottom of the tank. Gas with ethanol has a shelf life of about 30 days. Ethanol will also act as a solvent on the fuel line, creating a gum on the inside of the line and make the line very brittle. The gum will eventually migrate into the carburetor and foul it. I would strongly suggest that you replace the fuel line with Tygon or any other ethanol safe material, I would also swap out the fuel filter or add an inline one. Do not store the generator full of fuel, store it empty. Check out the website to see if ethanol free gas is available in your area. It will last much longer especially with a little bit of Stabil in it. Good Luck,Michael Burke

Dec 01, 2011 | Coleman Electrical Supplies

1 Answer

Engine surges

Hi Johnny,
I think the heart of your problem lies with the ethanol content in today's gas. It has at the very least 10%. The problem with gas containing ethanol, it only has a shelf life of about 30 days. What happens is the ethanol absorbs water from moisture in the air. The ethanol and water bond together and have a higher density than the petroleum based gas on top. It is exactly like oil floating on water. When this happens the octane rating of your gas drops dramatically, that's problem number one. Problem number 2, let's say your generator has a 10 gallon tank. Each gallon containing 10% ethanol, 1/10th of a gallon times 10. After about a month or two in a humid area you have a full gallon of water and ethanol sitting on the bottom of your tank. The best generator in the world will not run properly with this garbage sitting at the bottom. Problem number 3 ethanol is a strong solvent, it will deteriorate your fuel line. It will gum up the inside and make the exterior brittle. I would strongly suggest that you replace the fuel line with Tygon or any other ethanol safe fuel line and replace or install an inline fuel filter.Check out the website to see if ethanol free gas is available in your area. Here are two products that I strongly recommend Sea Foam and Sea Foam Deep Creep. I would completely drain the tank on your generator, install the new fuel line, spray a liberal amount of Deep Creep into the fuel line and let it sit for about an hour. Then drain the fuel bowl, fill the fuel line again with Deep Creep and let it sit for a little while. With the fuel bowl off, you should be able to lift the float and have smooth action with the float pin, no sticking the Deep Creep should flow smoothly when the float is lifted, after this is done re-assemble the carburetor and attach the fuel line to the tank. Add enough gas to run the generator for about 20 minutes and then use the Sea Foam. I have had stunning results from Sea Foam, I am not affiliated with this product it just works great and that is why I recommend it so strongly. Try to get the spray can of Sea Foam because that will be the easiest way to get it into the carburetor while it is running. Bring the generator outdoors after you have added a little gas to the tank remove the air filter from the carburetor and start the engine. Spray the Sea Foam directly into the carburetor, do not spray so much that it stalls the engine. After a spray or two you will get a feel for how much you can spray without stalling. Now the fun begins. Sea Foam removes carbon fouling from the engine and cleans the jets in the carburetor and it does this incredibly well but it produces an amazing amount of smoke, this can be very alarming at first but do not worry this is absolutely normal. You will be stunned by how much carbon gets burned out. Close the windows in your house and tell your neighbors in advance so they don't call the fire department. There will be that much smoke. Intermittently spray and let the fouling burn out. Do this about four to five times then spray a bit in the gas tank and let the generator run until it is empty. After the generator is empty add a little Sea Foam to the crank case oil, read the can for the proper amount. Store the generator empty. Sea Foam has stopped valve tapping, erratic float problems, rough idles and hard starting issues for me, It is an amazing product. I know that the desire to have a full tank in the generator for when the power goes out is very strong but it will cause you nothing but grief in the long run. You are better off finding gas cans that are air tight, they will not allow moisture to be absorbed into the ethanol and you will have a much longer shelf life. When the power comes back on I use a kerosene pump to empty my generator and then I run the engine dry.By using this method I have an extremely dependable machine that starts on the first pull every time even after sitting for over a year.Sorry for being so long winded but this is what really works and for those that also read this post who are not mechanically inclined, the long winded explanation gives them a clearer idea on how to solve this problem. Good Luck,Michael Burke

Nov 28, 2011 | Coleman Powermate Powermate 5000W...

1 Answer

06 Stratoliner, rough idle, stalls at stoplights, some backfire. It does this only sometimes, other times it runs good. Yamaha mechanic replace battery, plugs, cleaned air filter, checked computer, checked...

Hi, Jortega22 and the usual suspects are:
1. Severely discharged or a damaged battery should have 12.5 volts or better and be able to pass a proper "LOAD" test if necessary your battery may show 12.5 volts or more but have little or zero amps and must be replaced.
2. Failed alternator/generator and or voltage regulator.
3. Loose or corroded battery terminals and or cables especially the "NEGATIVE" cable, look for loose, corroded, or broken connectors inside the cable harness at "BOTH" ends.
4. Failed main circuit breaker or ignition switch, check for loose connections and continuity.
5. Failed system and or ignition relay, check for continuity.
6. Failed ignition coil, ignition/electronic module.
7. Failed CKP, CPS, CMP, MAP, TPS, or BAS sensor, corroded, loose or broken wire connector pins/sockets.
8. Throttle cables and or idle speed improperly adjusted hot idle speed should be 950 RPM to 1000 RPM.
9. Fuel tank empty.
10. Fuel tank contaminated with ethanol sludge.
11. Water or dirt in the fuel system, or clogged filter.
12. Restricted, blocked or kinked fuel line.
13. Faulty fuel pump.
14. Faulty pressure regulator.
15. Faulty or clogged fuel injectors.
For more information about your issue and valuable "FREE" downloads that you need please click on the blue links below. Good luck and have a wonderful day.
Rough Idle Stalling and Misfiring
Yamaha XV19SW Service Manual
OEM parts for Yamaha
Yamaha ROADLINER XV19SW Owner Manual

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Oct 01, 2011 | 2006 Yamaha Stratoliner

2 Answers

Husky 5000w Generator with a Subaru engin. Starts great but when you put the choke into RUN mode the "throtle" rocks back and forth causing the engine to rev up and down. Any ideas? Run fine in half or...

Fuel system needs cleaned. Dirt or build up get's in the passages and it can not properly regulate the fuel/air mixture. Being it runs well in choke position I would suspect it is plugged on the idle passage. Sometimes you can add a very small amount of "Seafoam" to the fuel and let it run while slowly moving the lever to the run position and this will clean it out. It is also possible that the fuel tank has a small amount of water in it. Good luck and have a great day.

Feb 10, 2010 | Coleman Powermate Subaru 5000W Portable...

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