Mercury Fuel Hose Causes Issues

[BIGFISH.JZ]

I want to share some info that could save boat owners some headache and money. Before you hit the water this season please look at your fuel hose from tank to engine. If it's grey and doesn't have blue printing on it, you possibly have a section of the 10million miles of hose that mercury sold to all dealers in the late 80's- 90's with some still possibly being used in new boat rigging that falls apart internally. There is 3 types of lettering on merc hoses. Old hard grey with stamped lettering, soft grey with red print that fades quickly in the sun and stiffer grey with blue print. The soft hose with red print is the JUNK HOSE!! It has a rubber liner that disintegrates and plugs itself up at connectors and plugs fuel filters and carbs with chunks or a light brown 'powder' that looks like fine sand but feels like rubber. Most repair shops will replace filters or clean carbs and send it home running great... Then the same thing happens... Over and over. If you have this junk hose remove it and cut it into 2" bits and dispose of it. Or give it to your brother in-law or father in-law if they have treated you unfairly. After installing new hose, flush system and replace fuel filters. I have seen this type of hose cause strange issues on over 100 boats. I can now, even spot it on oncoming traffic at 65 mph. I will loudly say it needs to be replaced but the other driver probably never hears my warning. It will last forever IF you ONLY use 91 non oxy but its not worth risking that NOBODY EVER has/will put cheap gas in the tank. It takes 2 minutes to examine and 10 minutes to replace. I recommend replacing it with black yamaha hose.

[Mike89]

thanks!!!

[Hookmaster]

This may explain the issue that has plagued my Yamaha 1999 F100 for a long time. It's a Lund boat and a Yamaha outboard which I believed was rigged by the dealer. It stumbles at times in the 2500-3500 rpm range. Idles fine and WOT is good with an occasional slight stumble. Had the carbs cleaned and it ran great for 4 hours, then started doing it again. I'm pretty sure it's the soft grey hose. I'll check to see if has any lettering when I get it out of storage. Thanks for the post.

[PRO-V]

Hook, check for water in the gas also. Had that issue once and it acted like that.

[BIGFISH.JZ]

Water in fuel or 'phase separation' is the #1 running issue I see every year or day for that matter. I always tell people that nobody has ever 'saved money' by using the cheap gas in their boat. I ask people if they are buying 91 oct and they say "of course I am" Then they go inside to pay and ask where they can find 91 oct fuel. Carbureted yammies are the pickiest about running on mediocre fuel. I have driven my cars, trucks and Mercs thousands of miles on fuel that a 90's yamahas won't fire up on. I believe all boats should have a water separating fuel filter. The large yamaha (big blue canister) ones are about the best. From what I've seen in 20 years in the marine industry yamaha outboard motors are as reliable as any, but the 80 and 100 hp have had specific minor problems that have stumped the best techs I know... More than once. If I see an EFI Yamaha come in the shop, 99% of the time I grab some 10w30 and a 5gh(69J)-13440-xx (filter) and nothing more. I own 9 boats and zero yamahas because I have a great sense of adventure and live for the unknown! 

[PRO-V]

Bigfish, I have a '93 Pro 60 Yamaha. Run 91 non-ox and Ring Free. Never have had an issue. Wondering, in your opinion is the Ring Free a big help?

[BIGFISH.JZ]

The 91 is crucial, I'm gonna be explaining phase separation soon, the ring free is not as crucial but it is DEFINITELY beneficial. I think yamaha has excellent products and have done extensive testing and research. If they recommend that you use a product, its because the life of your motor depends on it. Not because they want another $20 for some snake oil. If used as directed you are gonna be very happy with the results. I realize that you can't 'see' the benefits but that doesn't mean it is not working.

[Hookmaster]

I do have a water separating fuel filter on this boat. Maybe it's time to siphon everything out of the tank and start over.

[BIGFISH.JZ]

With the issue You're describing.... I would remove the filter and dump it in a glass jar. Let it sit a few minutes and examine to see if it is seperated into layers. If yes, siphon out and if you can access the fuel sender, remove it and use a rag taped to a stick to mop it dry. Replace fuel filter with new (filled with fresh 91). If gas looks ok and smells ok, I suggest new spark plugs. Look at wiring under hood to confirm tight corrosion free connections. I think plugs could be the culprit. Oh yeah... If you had it professionally winterized, they probably replaced the filter and it is probably full of 'shop gas' so take that into consideration.

Edited March 18, 2019 by BIGFISH.JZ
Properly winterized?

[hitthebricks]

It doesn't matter what brand motor you have,  what gas you use, weather or not you treat it, change them out within 15 yrs. the hoses fail and clog stuff up!  It is cheap prevention!

 

[leech~~]

1 hour ago, hitthebricks said:

It doesn't matter what brand motor you have,  what gas you use, weather or not you treat it, change them out within 15 yrs. the hoses fail and clog stuff up!  It is cheap prevention!

 

 

Good, point.  UV rays from the sun on a 15 year old plastic gas line is going to get brittle and crack up.

[BIGFISH.JZ]

14 hours ago, leech~~ said:

 

Good, point.  UV rays from the sun on a 15 year old plastic gas line is going to get brittle and crack up.

They don't make fuel hose out of plastic, leech, it would get brittle and crack up. The junk hose I'm trying to rid the world of, actually gets softer with age and from the outside it appears to be in excellent condition. Its difficult to convince people that they need a $50 replacement hose when they don't see anything wrong with the one they have, until I fillet it open and show them the loose rubber pieces inside. Mercury was aware of UV rays when they made this fuel hose, they didn't foresee the ethanol fuel that was coming soon to gas stations everywhere. Replacing your perfectly good (non red print merc) fuel line with the newer EPA approved hose and bulb required now, is terrible advice....

But that's just my opinion... I can fix it no matter what "improvements" you decide to perform in your driveway, its just money anyways. I wouldn't have any work to do, if every body listened to the professional advice of their friendly marine technician. I'd probably have to fish my life away then, but somehow I'm sure that I'll be buried in work orders again. 

[leech~~]

4 minutes ago, BIGFISH.JZ said:

They don't make fuel hose out of plastic, leech, it would get brittle and crack up.

 

Huum, seems like a brittle and cracked up hose made out of some kinds of plastics to me?

 

 

The replacement hose on my Merc sure seems to be made out of one of the 10 or so different plastics used for fuel line 

 

[BIGFISH.JZ]

How bout this....?

"Quicksilver Fuel System components are are made of UV resistant materials and prevent hardening. All materials must meet Mercury’s strict engineering specifications for UV hardening resistance, alcohol absorption, fuel flow restriction and leakage. The result is a product that lasts longer and is more reliable."  Not my words, straight from the manufacturer! The pic I posted is me... The hose and liner are both super soft and even supple, even being caked in an oily skin from the environment it was in, just like the 100+ other junk merc hoses I have had the pleasure of destroying and replacing.

[BIGFISH.JZ]

I just found a few others who may or may not know what they are talking about...

"2018 · Is your fuel line from the tank to the motor a bright silver color with red printing on the side?? If so, put it in the trash."

 

"Optimax engines. The FIRST thing is to make sure you have the proper fuel lines. In older lines, the ethanol breaks down the linings and sends junk into the fuel system. At best you will have clogged filters, at worst it blows the engine. You must, must, must get the right fuel lines."

 

"Check your fuel line from fuel tank to motor. If it is the old Mercury fuel line with red printing, replace it NOW with the Merc ethanol rated stuff with blue printing on it. Replace the primer bulb too."

 

 "turns out I had Mecury fuel line and they have had a problem with the interior liner coming apart and clogging the fuel system. As soon as my mechanic saw the fuel line, he knew what it was." 

These are direct quotes from people who found out about this issue first hand!! 

I would never steer any FM readers or service customers in the wrong direction. I don't repeat info from just anybody with an opinion. I have literally spent more time in boats during waking hours, March through November, than I have with my feet on the ground!! I won't comment or advise, without 1st hand knowledge. But, believe what you want, but I have good sources and care about educating those who may benefit.

[PRO-V]

Bigfish, how have Yamaha hoses held up?

[BIGFISH.JZ]

The only yamaha hoses that have been an 'issue' were the new 'quick connect' style they came out with years ago to please the EPA. The issue was that yamaha sent letters to all the buyers of motors equipped with these, saying there is a chance of the o ring failing and causing fuel leakage which, in turn, could POSSIBLY cause a fire. They recalled them but couldn't make/distribute new(old style) ones fast enough. We had customers that refused to use their boats until they got replacement hoses. I never saw one leak a drop. Then I would cut off the 'bad' ends from our pile of recalled hose and swap out the junk merc hoses with the yamaha hose. Usually, this was done by me FREE of charge to eliminate the hassle of contacting owner and explaining the problem. Dozens and dozens got free fix. So, the answer to that question is, they are excellent assemblies. They kink a bit easier than most and I've seen a few bulbs that were rock hard but I prefer yamaha hoses to any other.

Edited March 20, 2019 by BIGFISH.JZ

[BIGFISH.JZ]

If anyone still has the round plastic push and turn connectors on their yamaha, you should be able to get free replacement from your dealer. These were on 2005 - 2007 (?) Small and mid sized yamaha 4 strokes. If you have junk merc hose that needs to be replaced, go to a yamaha dealer and ask if they have a recalled (used) hose you could have or buy cheap. Might save some money. It's worth a shot once you see price of cheap after market hose assemblies.

[BIGFISH.JZ]

This is off a Ranger with a PRO XS OPTI from opener that wouldn't run. Cost of repairs =$500!!

[BIGFISH.JZ]

[BIGFISH.JZ]

This one WAS still in exceptionally good condition still.... replaced it anyways!!

[delcecchi]

Hmm, gotta take a look to see if they switched hoses when they put the Suzuki on my 98 Lund.