Mariner/Mercury Gas Hose Problems

[Locozodiac]

This is not a thread, just a warning note. Have in use a 2 stroke Mariner 05 HP with only 40 hours use from new, the first day of January took the engine for a morning cruise, made all the start procedures, engine started but soon went off, tried again, again, when my arm started to feel tired, threw the towel, a complete day of frustration, happens that we are in plain and sunny summer. At sight seemed a gas problem...

At mid day all the gas hose segments, filters and carburator were disassembled to be visual inspected, found dirt and plastic like obstructions in all the gas path, this engine has two main filters besides the gas tank, that was the reason for shutting off. Going further, the tank primary filter was removed, the primer bulb and check valves were disassembled, to my surprise found more of the yellow debris.

The causative is the internal plastic pipe that all Mariner/Mercury has in the interior of the gray hose to make the hose more firm. With time and gasoline this hose begins to rot and starts to obstruct all gas passages till the engine won’t start. Is a hell of a time to remove completely all the pieces inside the main gray hose, so better replace all the gray hose sections for a good quality gasoline hose and clean completely all gas paths.

When boating cannot risk your life using a cheap gas hose, Mariner/Mercury gray hoses are a shame, stay away from them. You can find this gray hose in many engine models, so be aware of the problem. Don't know if newer engines comes with a different better quality gas hose. Any comments are welcome.

Other technical issue: This engine has after the gas connection a small black and blue filter, see photo, wanted to know if this is a normal small filter or is a check valve/filter, still feels slightly obstructed, don’t have one new at hand so to compare. The issue is : Can the engine work safely with this filter removed and by passed, tried, but seems the engine has gained more power as from before condition, don’t know if it's safe to use it this way, any info available will be gladly appreciated.

Happy Boating

[Dirk Diggler]

Originally Posted by Locozodiac

This engine has after the gas connection a small black and blue filter,

Parts finder lists it as a "connector", the filter is the unit above it. So i would say it's a one way valve.

[Poly]

Is that a 2005 hose? Is there anything unusual about your fuel - e.g. high methanol - it looks like the plasticiser has leached out of the material making it brittle - I am surprised if that happens in 3 years (even at your high temps) unless there is a compatability issue.

[Nos4r2]

Is that the grey fuel hose with a woven core between the layers that failed?

[Locozodiac]

Originally Posted by Dirk Diggler

Parts finder lists it as a "connector", the filter is the unit above it. So i would say it's a one way valve.

Hola Dirk, yes, it seems that is a connector or check valve type (one way) will try to clean it better, what happens if this connector is completely by-passed. Have done the experiment in idle and you can hear the engine load (hear/feel more power) than previous. Anny comments/advise will be appreciated.

[Locozodiac]

Originally Posted by Polwart

Is that a 2005 hose? Is there anything unusual about your fuel - e.g. high methanol - it looks like the plasticiser has leached out of the material making it brittle - I am surprised if that happens in 3 years (even at your high temps) unless there is a compatability issue.

Hola Polwart, according to the engine cowl, the engine was manufactured july 2004, has remained in it's original shipping carton until opened to start operation about a year ago, has no more than 40 hours use. Our temperature is not high, as a related temperature plasticiser hose failure. The gasoline employed is the standard good quality 90/95 octane, no methanol or ethanol added. Seems a bad quality material, Tohatsu the original manufacturer does not employ this type of gray hose on their engines. The tank and hose are Quicksilver brand, seems made in Canada for US market.

The photo only shows 1/3 of the total plasticier removed, a hard 4 hour work including air + water injected at high pressure to completely remove all debris from the segmented hose wall, including lots of hand cleanning of all connectors, filters, primer bulb one way valves, etc that were also 80% clogged with tiny brittle hose plasticier debris.

[Locozodiac]

Originally Posted by Nos4r2

Is that the grey fuel hose with a woven core between the layers that failed?

Yes, you're right, incredible in such short time use...

[Nos4r2]

Thanks Loco. I've got some of that in use. I will check it.

[jyasaki]

That's pretty surprising. And somewhat sobering.

Are you sure you didn't get hold of a couple of tanks of that Brazilian E85?

Hard to believe that fuel line wouldn't stand up to fuel for a year.

jky

[9D280]

Loco,

That's either some totally underspecified hose, or like Polwart / Jyaski says, are you absolutely sure you aren't running an Alcohol mix? One way to find out is (I think - I don't know the engine!) have a look inside your carbs - if the brass bits are corroding badly there's every chance you got An alcohol mix in there. The high conductivity of the alcohol mix fuel accelerates sacrificial corrosion in the metal parts of the fuel system.

Out of cuiriosity, can you leave some of the outer sheath in a puddle of the fuel? Measure the length & diameter of the bit you put in, leave it for a few days & see how much (if at all) it grows. A big increase would hint at an ethanol content.

Mind you the engne would be running a lot less positively with E85 unless merc have tuned it to run on that stuff. Not be so big a difference with E22 in a "standard" engine.....

As you say, not good at all. good luck with the replacement hose.

[Locozodiac]

Originally Posted by jyasaki

That's pretty surprising. And somewhat sobering.

Are you sure you didn't get hold of a couple of tanks of that Brazilian E85?

Hard to believe that fuel line wouldn't stand up to fuel for a year.

jky

Hola Jyasaki & 9D280, In Peru we don't use ethanol/methanol mixed gasoline as as in Brasil, just standard gasoline mainly good quality 90/95 octane with normal cleaning aditives, works perfect in my other engines, the only difference is the color hose, gray for Mariner/Mercury, black and thick for the other Tohatsu's.

Bottom line: If any Ribnet user, uses Quicksilver brand Tanks with gray soft hose be aware you might experience the same problem, your engine will appreciate the precaution of having change it on time, so do you. This is just a plain expeculation, as I don't know if the bad quality hose has been replaced in newer Mariner/Mercury engines models.

Thanks all for the answers trying to figure out what might have been the probably cause of the failure.

Happy Boating

[samt]

I can't remember exactly, but when I've cut the mercury fuel hose for my outboards and the hire boats at work, I havn't noticed any extra lining insided???

Also, we've been through loads of the little mariners at work over the last 4 years, seen all sorts of crazy faults, but never had any with the quicksilver tanks and hoses. The bulbs tend to give up after a while though.