Cleaned my VST Tank... wanna see???

[jfbetz01]

Ethanol

There has to be something more at work there than ethanol in a 3 year old engine. I'm surprised the engine didn't lean out and torch a cylinder or 2 drinking fuel out of that chamber.

Yup, this motor has a lot of history with water damage. And I neglected to inspect the VST Tank when I was rebuilding several parts of the motor (stupid-stupid-stupid).

Would that include immersion in salt water?

[slads5874974]

There has to be something more at work there than ethanol in a 3 year old engine. I'm surprised the engine didn't lean out and torch a cylinder or 2 drinking fuel out of that chamber.

Agreed. No intentions to blame ethanol for this damage. But I still hate ethanol for many other reason.

[amahaork]

does gas tank vent has upward loop to prevent water getting into (gas tank) ?

[marchmadness]

I have 03 f225 and my vst tank looked like it was a year old . That looks like it was submerged and in salt water.That is not ethanol. I can't believe that worked. I would bite the bullet and buy a complete vst and lift pump and start fresh.

[pstephens46]

Well I guess it's a gd state secret where the water came from.

[slads5874974]

Well I guess it's a gd state secret where the water came from.

What is "gd state"?

Believe me, I wish I knew where the water and the gunk came from too and I wish I knew this all in advance. I have seen other VST tanks that were not involved with water damage/submerged, that looked awful and it was due to ethanol and probably lack of maintenance. But nothing where the rust an corrosion set in on the interior. More so with yellow thick gunk sitting at the bottom of the tank. My local shop showed me an example of a replacement job they did on a Tank. They showed me the tank they removed. Pretty ugly stuff. So I don't know how water could have got into the tank other than the fuel lines and water got into them some how. That tank is sealed shut and nothing should get in there but the fuel itself. I just don't know. My only assumption is the water damage/abuse was partial submersion (that specific side of the motor) on the side of the VST?

I have several lessons learned from this project. One good take away is I have learned about 85-95% of the components on the 2014 Yamaha F150xa and their functions. So I know the motor very well inside and out, and hopefully it helps with the future of the motor and its life on my boat.

The new pump arrived today. Looking forward to install and getting back out on the water for the fall run!

[oldmako69]

gd is "gosh darn" or something more acerbic if you like.

As I understand, Ethanol is hydroscopic and hydrophilic. Among other ways, it can pull moisture out of humid air through the fuel vent. Over enough time, significant moisture can accumulate as water in the bottom of the tank. Eventually some of that crap gets sent to the engine.

Buying old ethanol from out of the way gas stations and sleepy marina's give you the opportunity to pump old crappy E10 directly into your tank at no extra charge. You get a free head start!

Also over time, E10 also suffers from phase separation. This crud accumulates in the bottom of fuel tanks, fuel filters, VST's, carb bowls. I used to rebuild my Holley 4 barrel every other season on my last boat. It ALWAYS had orange sticky crap in it even though I used a Racor water sep fuel filter and regularly sumped the bottom of the filter bowl to remove settled crud and water.

The HI PSI pump on my port motor had a thin coat of rust on its exterior surface. Not nearly as bad as the one in this thread, but rust none the less. You could scrape it with your finger nail. These engines had only 125 hours on them, but that was over 12 years. How long did old fuel sit in the VST? Those tiny flakes of rust slough off and enter/clog the intake screen on the bottom of the pump. Small enough flakes go through the pump and then get stuck in the F filter and the injectors. And the moisture in the fuel causes the metal inside the pump to rust as well. That gets sent out to the injectors as well.

I now use Startron Enzyme fuel treatment with every fill up and Sta-Bil in the slow use months as well.

http://www.franklinfueling.com/media...-07-12-web.pdf

[rodbolt17]

shoulda just dunked the pump in a jar containing Yamaha combustion chamber cleaner overnight.
rust will be gone.

its NOT e-10.

it IS the US govt marine technician stimulous package.

man if I aint made a few coin off of it.

it affects all brands and all hull makes.

[pstephens46]

shoulda just dunked the pump in a jar containing Yamaha combustion chamber cleaner overnight.
rust will be gone.

its NOT e-10.

it IS the US govt marine technician stimulous package.

man if I aint made a few coin off of it.

it affects all brands and all hull makes.

So it is E-10? Or not? Or what?

[boscoe99]

So it is E-10? Or not? Or what?

I think he is suggesting that E-10 stands for a government run program to enhance the revenue of mechanics of all types and kinds.

E = Enhanced earnings.

10 = By at least 10% more revenue.

E15 = Enhanced mechanic revenue of at least 15%.

E85 = Enhanced mechanic revenue of at least 85%

We are from the government. We are here to help. We know what you should be using in your gasoline.

Boscoe the cynic.

[slads5874974]

Looking for some advice.

I installed the new Pump and hooked everything back up. Took the boat out for test run today with the cleaned VST Tank and new pump.

Still having the same issues with sharp loss of RPMs. I took a video today to show an example of the issue. You need to click on the image below and it will take you to the video. Sorry its shaky. Conditions weren't great today.

RPM Drop

I am wondering if my low pressure fuel pumps are not working properly or maybe is an issue with my Fuel tank and not venting properly. Seems like the VST tank is not getting the fuel it needs to pressure up the fuel rail.

Thanks in advance for any advice.

[99yam40]

Monitoring fuel pressures is the way to see if they are a problem

[fairdeal]

I can imagine that is the VST being starved;
As 99yam says, the best check is a pressure gauge on the fuel rail while you are running,
but you can learn a lot with a tool you already have installed - the primer bulb.

may need a second pair of hands - but when the engine bogs - does pumping the primer move fuel and keep it running?

as an aside - given the extreme conditions inside the VST - I would disassemble/inspect the lift pumps, in any case

[pstephens46]

I can't remember. Has the main fuel tank been cleaned? Is it possible that junk is still being dredged up?

Did you get a deal on this boat/engine?

[slads5874974]

I can't remember. Has the main fuel tank been cleaned? Is it possible that junk is still being dredged up?

Did you get a deal on this boat/engine?

I owned the boat way before I purchased the motor. Fuel tank was replaced professionally 3 years ago.

Motor was purchased in the winter.

And yes, both were a good deal. Even the motor with the current issues.

I am going to test the low pressure fuel pumps and see if they are clogged or malfunctioning. I will update once I finish up.

Thanks all!