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Honda EU7000is Rust Issue

3878 Views 85 Replies 17 Participants Last post by  Colt Carson, 
S
As a matter of background, I had my previous EU7000 for about 3 1/2 years and decided to sell it to upgrade to the current version with Bluetooth, etc. My previous unit was in pristine shape and no rust whatsoever and always kept in garage. I've had my current unit for just over 7 months. My neighbor also has the newer version, same unit but purchased about 1 year ago. When my neighbor asked for help with her unit, I also helped fill the gas tank. When removing the gas cap, there was a lot of rust on the fuel tank's rim where the cap connects. I thought that was very unusual for a relatively new unit and one kept in her garage. Also disappointed as I recommended the Honda unit to her. Then due to the recent storm, I too added a few ounces of fuel to the top-off level recommended in manual and noted the beginning of pitting (the beginning of rust) in the identical location of my neighbor's unit - the pitting/rust is under where the gas cap gasket seats to the fuel tank. Cap appears to seat firmly and snug in place so I don't think it's a bad gasket. My unit is also stored in the garage and partially air conditioned from house. I am totally perplexed as my previous unit didn't have any rust at all, was stored in identical location and have always used the suggested E0 fuel. Are there others that have the new version Honda EU7000is for over 7 months that have the same rust problem beginning? I'll get a photo of my neighbor's unit that will show terrible rust while mine appears to just be starting. I did coat the area with motor oil to hopefully slow down the rust.

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A
I'd spray it with WD40 when refueling. The metal mixture seems to need it to keep surface rust away.
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S
I wonder whether the deterioration of the metal is indicative of a lesser quality metal used in the newer versions as my previous unit was like new after 3 1/2 years without needing to add a protective coating like oil or WD40. Would you know whether the rusting area of the inlet consists of the same metal as the fuel tank or whether the inlet is attached somehow to the tank. I'll get a photo of my neighbor's unit to post as it does look terrible and it appears that rust particles have fallen into the inlet screen.
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OrlyP
I don't have a Honda but it's a common occurrence among metal tanks. This has also started happening to mine after about a year. What I did was put a dab of silicone grease around the lip... the same silicone grease I use on my flashlight O-rings. I'm hoping it would both protect the metal from exposure as well as preserve the rubber gasket and keep it malleable for a long time. It also works as a lubricant as it prevents the gasket from sticking and so it makes turning the cap on or off easier.

I don't store gas in the tank and it's completely dry but I anticipate that the silicone grease would immediately start to dissolve when I pour gas in, just due to the gasoline fumes alone. But I can always re-apply more silicone later.

I didn't use motor oil as some of the additives may have a detrimental effect on the gasket, long term. Silicone is safer on rubber.
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iowagold
watch the silicone as the honda eu7000is gen has a cat.
they now make drying socks for fuel cans.
wix makes them
pm if you need links.
darn fuel has water in it these days...
even at e-0...
i just checked clients Seperator filters for water on the e-0 tank...
one was full of water the other was 1/2 full.

i think it has to do with the moisture in the air getting sucked in with heating and cooling.

nitrogen gas blanket for the tanks?? just a thought...
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Dutchy491
When fuel gets used it gets replaced by the outside air, so if it’s humid out that dampness ends up inside the fuel tank. Over time the moisture collects as actual water and contaminates the fuel. So you can buy clean dry fuel….but that doesn’t eliminate water contamination. Too bad fuel tanks don’t have bladders like water pressure tanks do. Drying socks mentioned above are a great idea. I think that the occasional ethanol fuel run through the system completely will reduce moisture in the fuel system…
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B
I have the older version and have no issues with rust. I did switch from gasoline to natural gas, so I don't keep any fuel in the tank.
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S
Guess the general consensus is that moisture/water is causing the rust issue and not inferior metal. This brings me to another question: Generally speaking, is it best to keep tank completely full and use sock or keep completely empty and fill only when needed. Someone mentioned Marine Fog that I think is used to prevent rust in the tank. Is this product available on Amazon or is it a specialty product as I've never heard of it before? And is the Marine Fog used only under critical circumstances like marine use? Thanks for all the feedback.
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Dutchy491
Any small engine shop will have engine fogging spray. It’s a good idea, but is really meant for engine internals. Although spraying some in/around the fuel filler is a good idea. This spray is safe for emissions systems, if that’s of any concern…
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GenKnot
StormReady said:
Someone mentioned Marine Fog that I think is used to prevent rust in the tank. Is this product available on Amazon or is it a specialty product as I've never heard of it before?
Click to expand...

I use 2-cycle marine oil from Walmart to coat things that might rust and also use it in the carb, engine, and tank during storage. Even on the muffler (it burns off when used). It is inexpensive and blue in color so that makes it easy to distinguish from engine oil leaks.

As for the rusting that is occurring, I would mask it off and spray with something like Rust-Oleum to stop it. The oil coating won't last.
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Dutchy491
Very difficult to ascertain if any product sold is authentic or off-shore junk when buying off Amazon. Bogus NGK plugs come to mind 😵‍💫 I prefer to Support local businesses whenever possible…and enjoy the personal service.
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S
OrlyP said:
I don't have a Honda but it's a common occurrence among metal tanks. This has also started happening to mine after about a year. What I did was put a dab of silicone grease around the lip... the same silicone grease I use on my flashlight O-rings. I'm hoping it would both protect the metal from exposure as well as preserve the rubber gasket and keep it malleable for a long time. It also works as a lubricant as it prevents the gasket from sticking and so it makes turning the cap on or off easier.
Click to expand...
I designed and 3d printed a fuel cap opener for my gen as the cap is too wide and thin to get a proper grip so makes it very hard to turn, but now theres no effort at all to turn the cap..... I have it stuck on permanently.
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S
I was thinking more of something to only fog the fuel tank to prevent rust if I store empty so maybe this is not an answer. So is it generally best to keep tank full or empty on a Honda EU7000is that uses fuel injection rather than a carb? And I only use E0 fuel with Sta-Bil.
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Dutchy491
You’re going to run it every month or so right? Say yes!! So store it full with no E gas and stabilizer. Run the unit with a medium load, like a 1500 watt heater, for 30 minutes or so each time you exercise it. Top the tank off with the above gas as required. ps…for none efi generators be sure to drain the carburetor with the drain screw after each exercise. Turning the fuel off and starving the engine doesn’t get the last 2 tablespoons.
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drmerdp
Neither of my EU7000s are rusting in that spot. (Bluetooth and earlier version) I’ve had the BT version a year now. Both sit in my gen shed.
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OrlyP
It might be possible that you live in a place where there's high relative humidity. I live in a tropical climate and it's just a rust party all year round.

It gets worse if you live near the coastline or any body of water (especially salt water).

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S
Dutchy491 said:
You’re going to run it every month or so right? Say yes!! So store it full with no E gas and stabilizer. Run the unit with a medium load, like a 1500 watt heater, for 30 minutes or so each time you exercise it. Top the tank off with the above gas as required. ps…for none efi generators be sure to drain the carburetor with the drain screw after each exercise. Turning the fuel off and starving the engine doesn’t get the last 2 tablespoons.
Click to expand...
I run my 2600watt gen monthly with a 400watt load for 20mins or so, and I just switch off the engine without running it dry, with E10 fuel + stablizer, and no probs so far in 3.5years. Only just changed from E5 to E10 fuel though, But the gen seem to be running better on the E10 as it starts up faster for some reason.

But in countries where you have real high temps and humidity fuel left in the carb will go bad quickly?
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iowagold
StormReady said:
Guess the general consensus is that moisture/water is causing the rust issue and not inferior metal. This brings me to another question: Generally speaking, is it best to keep tank completely full and use sock or keep completely empty and fill only when needed. Someone mentioned Marine Fog that I think is used to prevent rust in the tank. Is this product available on Amazon or is it a specialty product as I've never heard of it before? And is the Marine Fog used only under critical circumstances like marine use? Thanks for all the feedback.
Click to expand...
yup marine fog an empty tank for sure!
and if you run fuel make sure the tank is full for less breathing of the tank.
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S
Where is marine fog sold? Is keeping tank empty and using marine fog better than keeping a full tank and using Stabil Marine? I do live in Florida so there is humidity but my previous unit owned for 3 1/2 years never showed any signs of rust. Always kept in garage partially air conditioned with a full tank, E0 fuel and Sta-Bil.
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sledman8002002
StormReady said:
Where is marine fog sold?
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Any decent marina will have it readily available on the shelf.
StormReady said:
keeping a full tank
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Thats what I do. My gen tanks are always full (no-ethanol) and ready to go treated with either Seafoam or StarTron, never an issue.
Bad enough when the power goes out after dark, I dont enjoy the frustration of stumbling around to do a fill in the dark.
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