A few years ago I put together a fuel line assembly to use a NATO jerry can as an auxiliary fuel tank for my Honda EU2000i generator.  It worked great for the roughly 20 hours I have on it.  I ran a test on it a couple of days ago and it failed.  

It’s this adaptor that turned out to be the problem, it no longer holds a vacuum.  


The adaptor plugged into the replacement gas cap


Just FYI, the whole thing


I’ve replaced it and my fuel line is working again but I have a few questions for those of you with some experience with these adaptors.  Is it normal for these things to fail like this?  I mean is it just a POS part that you expect to replace now and then?  Or did I just get unlucky with that particular adaptor?  Is there some kind of maintenance I should have done?  If it’s just a POS then I’ll just go ahead and stock a few spares until I figure out a better way to do this but a 20 hour life span kind of sucks.

TIA
Steve

If you are using a cheap Moeller or Sierra fitting they won't last. It's hard to tell from your pics if it's a Evinrude/Johnson style connector or a Merc/Yamaha.

I would switch to a factory outboard female connector they will hold up much longer.

Are there replaceable O-rings inside the connector?

The piece does not appear to be designed to come apart.

Moeller and it's Evinrude/Johnson.  I guess it's time to go shopping.

I'm currently on line running a similar siphon/squeeze bulb system on an older Honda 3500w unit... can you use a 1/4" line directly to the carb, and connected it to the squeeze bulb and feed line with a pair of male/female hose barbs?... the 1/4" line is a short section, and I can unscrew the connector barbs to completely run the carb dry

That might be possible but the way I'm doing it is a pretty clean setup.  I replace the fuel tank cap on the generator and run the line between that and the can.  I'd prefer this to trying to jerry rig something directly to the carb, given a choice.  It works great, provided all the bits and pieces don't fail.  There are a few different QD adaptors, I think I just need to find one that's a bit more durable.  Running the carb dry when I'm done using the generator is pretty easy on the EU2000i.

Understand, however many Q-C's have O-rings you 'pick' out with a pointy plastic or metal tool like a scribe, and then insert the new O-ring.

Your adapter has to have a way to seal and likely has this config.

There's a screw on the carb bowl IIRC, that makes it quick to drain it. May even have a hose attached, I'll look if you want...

This said, we never drain ours [several] and have no issues.

I'm sure you're right about there being an O-ring inside.  I took a closer look at it and still don't think it's meant to be maintained.  Given the plastic construction and cheap price I think it's designed as a throw away part.

Thanks, I'm very familiar with the carb on the EU2000i.  The screw makes it very easy and you're right, there is a hose attached that drops the fuel out the bottom of the generator.

I don't remember if fuel (gas) for marine use has ethanol or reduced ethanol. Ethanol from regular automotive gas may have eaten up the seal in the connection. Just keep a spare or two around. Then it won't matter.

more than likely a bad o ring, buna N "dries out" with contact to gas

viton o rings do better IMO

Well, it matters to me because I do keep spares.  In fact I had 2 of these still NIB in my box-O-spares.  This thing failed in 20 hours.  That’s potentially less than a single event in which I might need the generator.  I had no idea these things were such pieces of crap.  Given the number of outboard motors being used around the world I’m more than a little surprised.  Whether it failed because of “bad gas” or poor manufacturing doesn’t really matter.  I won’t be rewarding the manufacturer by buying more pieces of crap from them.  I’ll find a better built adaptor or I’ll go another way.  But hey, this is why I test stuff.  At 20 hours run time I thought I was in good shape.  Guess not.

You think a manufacturer of fuel line adaptors doesn’t know that?  If that’s the issue then the manufacturer should have used Viton.  A useful life of 20 hours is unacceptable.  Planned obsolescence is not something I’m going to reward with additional purchases.

Take a look at the quick connect fitting used on Tohatsu / Nissan outboards, they are far more robust than double prong style Mercury / Johnson / Yamaha fittings and are widely used in commercial marine engine applications. In 30+ years I have never seen one fail a pressure test and have tossed hundreds of brand X double prong styles in the trash that leaked.

Thanks, that’s the kind of experience I was hoping to find.  Between you and Akethan I’ll take that as a consensus of opinion and do some shopping.  

And thanks to everyone else who replied.  It looks like I’ve identified a hidden problem in my preps and now I have a direction to go for a solution.  I think I’ll call that a success.

OEM parts are almost always the best quality in marine fuel connectors, Tohatsu is the parent company of Nissan branded motors and parts that are more common in the states.

Fittings you need look like this:

Thanks again, I got part numbers for those two earlier.

I also found this old thread about changing O-rings in these (I think).  The ability to maintain these things isn't mandatory but it would be nice.

http://www.marineengine.com/boat-forum/showthread.php?249141-Tohatsu-8HP-Fuel-Line-Connector-ORing-replacement