Yamaha F150 mystery substance in VST tank

[99yam40]

probably from the burned up motor then

[Surfjones3]

I blasted the pump with carb cleaner and the same stuff came out, of course it’s quite possible it was sucked up from something in the tank so I guess theoretically it doesn’t rule anything out, but if I this is the only spot with any sign of the same material then I feel like I have no choice except to put the new pump in and hope for the best

[Donnie Coulsting]

Cut open the fuel/water separator and pull out the element. This will tell you if your issue is up stream or down stream.

[Keithbaja]

Welcome to the big "E" not good gas ! Seen VST torn up on the inside from E, pitting and metal chunks in the VST. Pot metal alumanan VST

[Keithbaja]

Don't know the first look I didn't get your pics ? Checking my post and saw your pics.. your "Screen/filter" isn't alumanan crap or fuel pump motor brushes dust. Need YR & Model #

[oldmako69]

Check out my thread "Turd Fuel Line". https://www.yamahaoutboardparts.com/...turd-fuel-hose


I don't know your engine so I cannot opine intelligently but I know a bit about this issue and you may find it useful.

On the V6 F225 the high-pressure pump pressurizes what amounts to a loop. The individual injectors are mounted within this loop. They open and close in response to signals from the ECU (?). They only take the fuel they need. Excess fuel is shunted back to the VST. The VST clogs. Why and with what is the question. Here is what I know...


1. In my case, I believe that the interior core of the fuel line (the pressurized fuel loop) is rotting because of the Ethanol. These tiny bits clog the Hi PSI pump intake. They're black and vary in size and shape. Up to the size of pepper flakes. Those flakes small enough to get through the screen will eventually foul the injectors.


2. The insides of some HI PSI pump is rusting and rotting because of Ethanol's affinity to carry water solution. We're talking small amounts of water, not something that you're Racor will catch. But enough to cause rust. That rust gets passed to the injectors and finds its way back to the VST. I have read online of guys who take their failed HI PSI pumps and cut them in half. They are filled with rust.


3. IF your VST won't stay full, your HI PSI pump will fail. It overheats and dies early. $400 for a stupid 25 dollar pump is nuts.


4. SOMEONE on Amazon and or eBay used to advertise an aftermarket fuel pump with ZERO metal. I am unable to find it.
Perhaps it would last longer?


5. This HIGH-PSI pump. ------->>>>>>. https://www.ebay.com/itm/29139369582...%3AMEBIDX%3AIT. Fits my engines. I have run them for the last two years. Check out the price.


This LOW-PSI pump. --------->>>>>. https://www.amazon.com/Mercury-88824...AFP+-+69J34410. Fits my engines. I paid 40 bucks for my first one. 100 for the second. Who knows what they cost now.

My suggestion is to look elsewhere for your engine's pumps. You may find a suitable replacement for a hell of a lot less money.
Sorry to hijack the thread but I have scoured the web for info on these issues since I first bought my boat. This post may be of some help in the future. Good luck with your engine.

[oldmako69]

Check out my thread "Turd Fuel Line". https://www.yamahaoutboardparts.com/...turd-fuel-hose


I don't know your engine so I cannot opine intelligently but I know a bit about this issue and you may find it useful.

On the V6 F225 the high-pressure pump pressurizes what amounts to a loop. The individual injectors are mounted within this loop. They open and close in response to signals from the ECU (?). They only take the fuel they need. Excess fuel is shunted back to the VST. The VST clogs. Why and with what is the question. Here is what I know...


1. In my case, I believe that the core of the fuel line loop is rotting and being eaten by the Ethanol. These tiny bits clog the Hi PSI pumps intake. They're black and vary in size and shape. Up to the size of pepper flakes. Those flakes small enough to get through the screen will eventually foul the injectors.


2. The insides of some HI PSI pump is rusting and rotting because of Ethanol's affinity to carry water solution. We're talking small amounts of water, not something that you're Racor will catch. But enough to cause rust. That rust gets passed to the injectors and finds its way back to the VST. I have read online of guys who take their failed HI PSI pumps and cut them in half. They are filled with rust.


3. IF your VST won't stay full, your HI PSI pump will fail. It overheats and dies early. $400 for a stupid 25 dollar pump is nuts.


4. SOMEONE on Amazon and or eBay used to advertise an aftermarket fuel pump with ZERO metal. I am unable to find it.
Perhaps it would last longer?


5. This HIGH-PSI pump. ------->>>>>>. https://www.ebay.com/itm/29139369582...%3AMEBIDX%3AIT. Fits my engines. I have run them for the last two years. Check out the price.


This LOW-PSI pump. --------->>>>>. https://www.amazon.com/Mercury-88824...AFP+-+69J34410. Fits my engines. I paid 40 bucks for my first one. 100 for the second. Who knows what they cost now.

My suggestion is to look elsewhere for your engine's pumps. You may find a suitable replacement for a hell of a lot less money.
Sorry to hijack the thread but I have scoured the web for info on these issues since I first bought my boat. This post may be of some help in the future. Good luck with your engine.

[Surfjones3]

Thanks oldmako that’s really good information. I’m still dealing with some issues I really couldn’t find any source for this other than the VST. The engine is a 2014 f150xa the lines all looked so clean it’s hard to believe that my lines could be rotting so soon especially since I run the boat quite a bit. I ended up dropping $400 for a new fuel pump, I did consider some of the cheaper ones but everyone said to use only Yamaha parts. The issue I’m having now is the engine is running good at WOT @5500 and higher RPMs, it idles fine around 700rpms when I throttle up slowly around 1100-1800rpms the engine is missing and sputtering. If I throttle up fast it doesn’t occur. This was also happening before the old fuel pump went. So to complicate the matter more, I’m not sure if the pump just rusted out, I’m missing some issue that’s causing the VST to run dry and burn the pump out or the fuel system is clean and there is a idle control sensor or TPS issue. I was reading another post and it stated the ISC doesn’t do anything after 1800rpms, I don’t want to start just replacing expensive sensors based on a guess but I’m not sure how to test the ISC and I feel like everything in the fuel system has already been addressed

[TownsendsFJR1300]

I'm not sure how to test the ISC and I feel like everything in the fuel system has already been addressed

When you turn the engine off, do you hear a "rattling" for about 2 seconds from the ISC? You should, helps to hear with the hood off.

Also, on cold start up, idle should be slightly higher, then drop down to 700 or so once warm.

Here ya go: https://vimeo.com/264625510

[Surfjones3]

After going through everything and still having an issue I decided to go back into the VST. Based on oldmako’s experience I decided to replace all the HP fuel lines in the VST loop, the gas and filter were pretty clean. When got to the Line from the fuel pressure regulator to the fuel cooler rail I noticed a lot of black gunk on the fitting. When flushed with carb cleaner the same black crap comes out. I’m sure this is the culprit for all the issues, the rotted line probably went to the fuel rail so I’ll have to blast them and clean that really well. I think it’s ridiculous that this line failed in a 2014 that’s used a lot and even more ridiculous that Yamaha wants $107 for a 8in run of line. I’m also wondering should I replace the fuel pressure regulator? my concern is it’s gotten the gunk inside and is not functioning properly but I’m not really sure how to tell if it’s working and it doesn’t flush when I run carb cleaner through it. I will post and update once I get everything back together and take a run 2175A74E-E938-48BC-9FD3-A4DD7A9759B7.jpeg

[rejesterd]

When there's no incoming pressure, the valve inside the regulator is sprung closed. So you can't spray through it. You'd have to pressurize the line to a similar pressure that the fuel pump provides (like 40 psi or so). But the majority of any loose gunk would be on either side of the valve (not on the valve seat itself). So I would just spray into both ends, and flush it out at both ends.

[oldmako69]

Surf,

If you get a chance, would you mind slicing that hose open along its axis and snapping a pic of what's going on inside of it? So many people have had issues with these engines that you'd be doing us all a great favor.

When I went to speak with the local Yam mechanic he simply suggested throwing dollars and this and that in an attempt to solve my issues. I had already tried everything he suggested, so I neglected to hire him to help me. Cleaning the Hi PSI pumps intake screen every ten hours is not maintenance, it's a giant inconvenience. And coming in from 40 miles out with a sick motor is even bigger.

Not to mention if I had to pay a mech to clean that screen every time X 2 engines.

Thanks for the follow up.

[Surfjones3]

Surf,

If you get a chance, would you mind slicing that hose open along its axis and snapping a pic of what's going on inside of it? So many people have had issues with these engines that you'd be doing us all a great favor.

When I went to speak with the local Yam mechanic he simply suggested throwing dollars and this and that in an attempt to solve my issues. I had already tried everything he suggested, so I neglected to hire him to help me. Cleaning the Hi PSI pumps intake screen every ten hours is not maintenance, it's a giant inconvenience. And coming in from 40 miles out with a sick motor is even bigger.

Not to mention if I had to pay a mech to clean that screen every time X 2 engines.

Thanks for the follow up.

I will definitely do a dissection of the line and throw a photo up, what sucks is we are forced to use that same part because of the way it is shaped I tried using my fuel line but I can’t get it without it kinking, I should have went through the lines when I did the pump but all the Yamaha guys said it was to new and it would be very unlikely That a line failed on the high pressure side

[Joefiore1]

Having exact same issue with same engines

[Keithbaja]

I can write a novel about E gas. I work on many types of marine PWR plants. So far,, the best I can recommend is "Star Tron" one of my friends is the top seller of marine parts in this area. I trust his expert opinion. With feed back from from diy's to all the shops in monterey Bay area. If your motor is slightly older, replace fuel lines with upgraded, E rated parts
And you know,, say a pray.. I have a TSB from Mercury Marine that in this market has, can ,will go bad !!this fuel is so pissy that they won't sell it at small airports.. on another note: I don't sea anyone hear ever talk about "Salt Away". Great snake oil. But don't rinse it out. First (with muff's) leave on fresh water. Then introduce the S/Away. And turn motor off. Leaving the damn stuff where it should be.. in da motor