VST Tank Issues caused by heat from Engine?

[rib4charter]

So My boat has been in both freshwater and saltwater. I also had the tanks pumped out, and then the vst filter cleaned, then the problem still happened after e10 added where I get this buildup that looks like sand. I think the challenge is that there are microscopic particle of sodium sulfate in the ethanol from the manufacturing process, shipping, and storage. I am also wondering if they use salts to reduce moisture in the fuels. What is happening from what I am reading online is that the VST tank being aluminum is mounted next to the engine block and this takes on a treemensous amount of heat that goes into the VST Tank. The article from the link below says this:

http://www.txideafarm.com/ethanol_fuel_properties_and_data.pdf


The second most important property is "volatility". This is customarily measured by RVP, but latent heat and boiling point or initial boiling range play important roles. During cold start, there must be sufficient fuel actually vaporized during the compression for there to be a flammable mixture for the spark plug to ignite.

RVP is measured at 100 F, for which ethanol?s RVP of 2 psi already "looks low". If this pressure were measured at colder temperatures, the ethanol vapor shortfall looks even worse: there is very little sensible evaporation going on below about 50 F. The higher latent heat of evaporation compounds this effect. That?s why a little gasoline in the blend is beneficial to cold start, or else one must use a start canister of something flammable and volatile, like gasoline, to prime the engine for starting.



I wonder if the ethanol is evaporating in the VST tank due to the high heat levels and this is releasing the micro deposits trapped in the fuel (which are getting by a 2 micron filter) which then get stuck on the VST filter screan. Think of it as boiling water. If you boil all the water out of a pot, you get salt deposits left at the bottom. The VST Tank gets to hot for the ethanol blend. The more ethanol % you have the worse it gets. The more water the ethanol has trapped in the, the worse it gets. If you have no ethanol, no water gets absorbed. The problem is that the startron fuel stabailizer may allow the "water" to pass from the fuel tank, to the vst tank, and when the ethanol vaporizes, the salts in the water get released, thus causing the deposits. Most people have said that it is sodium sulfate that is in the bottow of the vst filters. You wonder if you need some sort of heat shield on the vst tank. Or a VST tank that can handle ethanol and be an insulator.

Any thoughts Rodbolt????

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

People have tested the residue at the bottom of the VST Filter and it comes up as sodium sulfate which is what Dow Chemical references in the following web link as being an issues with Ethanol Fuel

From Dow Chemical
http://www.dow.com/PublishedLiterat...seps/pdfs/noreg/177-02148.pdf&fromPage=GetDoc


Sodium and sulfate removal from Fuel Ethanol
In many cases, sulfate is present in fuel ethanol as salt of sulfuric acid and common ions such as sodium. Both components are of concern; the sodium is of concern for deposits that can form in engines and sulfate as a contributor to sulfur emissions and air pollution.
The most direct approach to removing both of these contaminants is with a deashing resin pair consisting of DOWEX? 88 and DOWEX? 66 ion exchange resins. The DOWEX 88 resin is used in the lead position to remove cations such as sodium, calcium or iron, and to prepare the sulfate for removal by the DOWEX 66 weak base anion exchange resin. In addition, the DOWEX 66 resin will remove organic acids.

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

It only would cost 1 cent per 1000 gallons of ethanol, but my cost for using ethanol gas is now $2,000 in engine repairs per the 100 gallons I have used.

 

[99yam40]

Re: VST Tank Issues caused by heat from Engine?

very interesting post. Does anyone use it to remove anything from the ethanol?
makes you wonder why our government is forcing the use of this fuel when the cost in fuel to produce it is more than the savings in fossil fuel. By the time they prep the land,plant,fertilize, cultivate, harvest, ship, process, and then ship and blend and distribute the blend it would be more cost efficient to just use the oil that all uses to run the motors directly

 

[rodbolt]

Re: VST Tank Issues caused by heat from Engine?

because E fuels are the biggest scam ever shoved down joe taxpayers throat.
its not the heat from the VST, in fact there is very little heat and the 4strokes have fuel coolers.
its the sheet fuels we are forced to use.
the gas tank on your EFI automobile is a VST tank, it gets hot as well

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

Rodbolt,

My understanding is that the engine temps are between 183F to 193F on the F225 and normal operating temps. Ethanol fuel will boil at 174F and when it boils it releases the deposits in the fuel. Since the VST tank is mounted to the engine and is made of aluminum which absorbs the heat after you run hard it is not a stretch to get the VST tank temerpature above the point where the ethanol will boil leaving deposits. The vst tank also lowers the pressure in the tank which causes the boiling point to drop even further.

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

An automotive systems is also a sealed fuel system that is preassurised which raises the boiling point and the fuel tank and vst tanks are kept far away from the engine so it is not exposed to the heat.

 

[seahorse5]

Re: VST Tank Issues caused by heat from Engine?

Ethanol in high concentrations such as in phase separation can strip the anodizing off aluminum items such as fuel tanks and vapor separators and corrode, pit, and etch the remaining metal. Those particles also get into the fuel system and some get through the filtering media to settle elsewhere in the system.

A good article on ethanol and its effects on boats and motors was in Trailer Boats Magazine a while back.

http://www.trailerboats.com/output.cfm?id=2342377&sectionid=317

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

No question it can, but I just replaced the VST tank with a brand new one because the old one corroded and the problem came back immediately. I am going to pull it apart again early next week to see the condition of the tank. From what I am hearing from others the VST tanks just have the deposits stuck to them and can just be cleaned as it is just the sodium sulfate stuck to the surface.

 

[seahorse5]

Re: VST Tank Issues caused by heat from Engine?

Besides sodium sulfate, white deposits in the VST have also been found to be calcium, salt, or aluminum oxide. Each is from a different cause.

 

[rodbolt]

Re: VST Tank Issues caused by heat from Engine?

the F225 VST is mounted on isolators,the F225 has a fuel cooler that uses a liquid to liquid heat exchanger to cool return fuel from the fuel rail.
sheet fuel is simply sheet fuel and the only way to deal with it is pump the tank,dispose of the sheet and start fresh then kep it that way, or take up golf.

rib4charter
automobiles use a fuel tank as the VST, most modern stuff has the pump mounted in the fuel tank and the fuel tank takes the return fuel and cools it by the mass of fuel in the tank.
4 stroke yamaha EFI motors have fuel coolers.
oneday you may see boats wth tank mounted pumps but i doubt it.
totally different market.
when that yamaha leaves japan in a crate yamaha has NO clue what type of hull the product will get bolted to.
I am all for alternative fuels but Ethanol is a big scam that is making some rich and killing the rest of us.
keep writing your congress and senate and lets get rid of the scam.

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

Rodbolt,

I agree with you. The government F me one more way. This ethanol issue is a big f u to boaters, but boaters have no power against the farm lobbyists who actually pushed for this crap. I now have to drive my boat 30 miles to fuel it from with the only 100% Gasoline pump in the area. I no longer feel comfortable running any ethanol at all into the engine as it will cause the problem regardless of how fresh the fuel is and how clean it is. This is happening anytime I have had any ethanol fuel no matter how fresh and clean it is. I have had my tanks pumped twice, and cleaned.


Seahorse
As far as sodium sulfate, calcium, salt, these seem to be from the manufacturing process. Aluminum oxide seems to be coming from phase seperation that corrodes the tank as the very corrosive ethanol gets seperated out and its corrosive properties increase once water gest trapped in the tank. You can stop the aluminum oxide particle by preventing the phase seperation by keeping the tank full and using stabil or startron, or both. Regardless of the what the deposit is, all these are deposits that get released when the ethanol fuel boils in the vst tank. When I clean my tank out, I am going to strap an electric thermmometer to the outside of the vst tank so I can read the temp of the VST tank to confirm how hot it is getting.

 

[seahorse5]

Re: VST Tank Issues caused by heat from Engine?

Let us know the temps you find out, but I do doubt that you will find fuel temps of 183? to 193? inside the VST.

Calcium and salt come from water in the fuel or phase separated liquid. Along with the ethanol these and other compounds can also form acetic acid which also can affect aluminum parts while the motor is inactive.

aluminum oxide can be from the fuel tank but also the VST and other aluminum parts in the fuel system.

No matter where is comes from, most of the fault is the ethanol mixtures that were forced upon us.

the only good thing about it in this economy is that it is keeping the service departments very busy and dealers in business while boat sales are in the toilet.

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

I don't think you have to get to the 180F temerature level to get the ethanol fuel to boil. When you throttle up to full throttle, the fuel pump tries to draw fuel into its inlet causing avacum on the fuel. The higher the pump speed the higher the vacum. When you induce a vacum, you lower the boiling point. This means it may only take 125 to 150 degree temps to get the ethanol fuel to boil which is not a stretch inside the cowling.

I don't have all the tools to test this but if you connected a vaccum gauge to the vst tank you could mearue the amount of the vaccum created which then would allow you to plot out the temperature at which the fuel would start to boil as they publish a boil curve on Ethanol. Once you did that you would have to measure the internal temperatures inside the VST to see what the actual temps are. Once you know the temerpature and the vaccum level, you could then reference the chart to confirm you are getting ethanol fuel boil in the VST. To confirm you could take a sample of the fuel in your tank put it in a beaker with a vaccum pump and thermometer attached. If you match the vaccum pressure and temperature to what you read going on in the vst tank you should get the same boil point. Once the fuel was boiled away, you would be then left with the deposits in the the bottom of the beker. If they match the sample in the vst tank, the thesis is confirmed.

On the other had as Rodbolt said, I could just take up golf but I may encounter more issues with my slice.

 

[99yam40]

Re: VST Tank Issues caused by heat from Engine?

I would think that the VST is kept pressurized by the other pumps.
If you end up pulling a vacuum in the VST it would mean that the lift pumps and/or filters are bad. And the motor would not run properly. Just my thoughts.

 

[rodbolt]

Re: VST Tank Issues caused by heat from Engine?

the electric lift pump feeds the VST,6"hg max on the feed pump intake.
the VST pump simply draws from the tank,which is vented to the air, feeds the rail.
what the rail doesnt use is fed back to the VST through a liquid to liquid heat exchanger(fuel cooler),

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

Took apart the VST tank, sure enough, the small sand like deposits were blocking the vst filter screen. There is no way these deposits are getting through a 2 micron filter and even the gas filter on the engine. You can rub them between your fingers and feel the grit. The VST tank showed no signs of corrosion. Taking a look at the vst tank, while the back of it is on an isolator mounting plate, it is still very close to the engine block. I pulled open the cover and the tank is hot to the touch.

Looking at the setup, of the vst tank there are vacum lines at the top that pull the vapor out of the tank and then you have the high pressure fuel pump inside the tank. Between these two draws on the tank, there is no question that the pressure drops inside this tank. This combined with the proximity to the engine head and an alluinum VST tank which absorbs heat from the engine is creating an environment for the ehtanol fuel to boil. When it boils it is releasing the sodium sulfate and other molecules the ethanol traps when it absorbs water. These particles build up, and then block the vst filter just enough that you can't get the throttle above 3/4 as you can't get enough fuel to the engine.

The solution:

1. The 2004 Yamaha F225 engine can not run on any ethanol fuel. I have talked with 5 owners of this engine year and we are all having exactly the same issue. After about 30 to 40 gallons of fuel your VST tank clogs up. You can only run 100% gasoline in this engine regardless of what the owners manual says that it can handle 10% ethanol. It can certainly burn 10% ethanol fuel, but the VST tank problem is a recurring definable problem that is directly linked to any ethanol fuel, not just bad ethanol fuel.

2. Heat shield protect your VST Tank from external engine heat. There is enough space to glue on a heat shield cloth they use in cars under floormats and to protect hoods of cars from paint blistering. You can see it here http://www.heatshieldproducts.com/heat_shield_cloth.php . I am ordering this stuff for the next VST filter cleaning I will do in a couple of weeks. The plan will be to cut the fabric to closely fit the vst tank to keep the radiat heat from getting to the fuel. I also noticed a few of the fuel lines get close to the engine header as well and I may wrap them as well. This seems like a relatively low cost way of keeping the heat from the fuel in the VST tank and will hopefully keep the Ethanol fuel (if you have to run it) from reaching the lower boiling temperature due to the reduced pressure in the tank.

3. Yamaha should man up and help owners with this issue by at a minimum providing a different VST tank design that can be retrofitted. My sense is one made out of a high strength plastic that is resistant to ethanol so it won't corrode and will reflect heat ( or not absorb it) would be an easy fix. Also it would be great if Yamaha designed a VST Tank/filter that can be changed without taking half the engine apart. There is a space where the VST tank drain is located that you could access. Worst case, make it so all i Have to do is pop the intake off which I can do on the water if need be. This is not a hard repair to do and should be offered as an upgraded part for the F225.

4. If you have a F225 that keeps having the VST Tank, please post here what year your engine is, what fuel you are running, at what solutions you come up with it to fix it especially if 100% gasoline goes away in your boating area. This is a problem that we should be able to fix.

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

Taking a look at the VST Tank this weekend. There are two vacum lines attached to the top of the VST Tank, they feed into the intake manifold. When you throttle up full throttle, this creates a tremendous amount of air flow in the manifold which is what creates the low pressure and sucks the vapor out of the vst tank into the intake manifold. This sucking action reduces the pressure in the VST tank. Also, when the VST pump runs at full speed the suction on the intake of the pump also reduces the pressure. The fuel coming into the vst tank is not under pressure as Rodbolt said it is just a lift pump so it doesn't balance out the loss of pressure created from the vacum lines at the top or the high pressure pump sucking out the fuel in the vst tank. Researching VST tanks I came across this one. They reference the issues of low pressure creating fuel boiling in the VST tank and how theres solves this.

http://www.kinsler.com/Cat_32_Pgs/Cat_32_4_09_Pg_115.pdf

Interesting enough, they say that the gasoline can flash boil at the inlet of the fuel pump. Add ethanol to the mix, and it will boil as well, but the problem is when ethanol boils, the sodium sulfate trapped in it gets released. 100% gasoline doesn't abosrb water, that is why the water seperator filter works. Ethanol can abosorb water and sodium sulfate is disovable in water which means it is trapped in the Ethanol fuel which is why it gets past even a 2 micron water seperator filter. If it flash boils at the inlet of the fuel pump, guess what is right there? You got it, the VST Filter screeen.

They solve the issue by making sure the VST tank stays pressurized, which keeps the boiling point from dropping on the fuel. Rodbolt, is there I don't t a pump coming from the engine that holds the VST tank at a constant pressure through its entire operating cycle or is just a return line?

In addition to the solutions I proposed above, here is probably the most basic one, NO HOLE Shots! If you slowly throttle up you may not get the flash boil as well as some of the vaccum pressure may be redueced there is not an immediate huge amount of air and fuel needed. This may allow the lift pump to keep the vst tank at a constant level of fuel which would not create as much of a vaccum. If the VST tank could maintain a constant level of pressure and still vent the fumes we would be done with Ethanol clogging VST filter is my guess.

 

[clanton]

Re: VST Tank Issues caused by heat from Engine?

Good information, I would like to see the VST temp after a hard run.

 

[rib4charter]

Re: VST Tank Issues caused by heat from Engine?

So after researching this issue and confirming this problem is more widespread that what I first realized I have come to the following conclusions, either the VST tank needs to be completely redesigned by Yamaha or you can't run any ethanol fuel. I have spoke with 2 top notch dealers an they keep running into the same issues over and over again and Yamaha has no responses. I have talked with people that have two motors running on their boat drawing from the same tank and one has the issue with the vst filter the other does not. Why the difference? One engine is running hotter or the fuel is getting hotter which is causing the ethanol to boil away in the vst tank leaving the deposits. I had this happen in as little as 8 gallons of fuel. Here is my final solutions to fix this

1. Don't run ethanol period
2. Keep the heat away from the fuel lines and tank
3. Yamaha needs to man up and redesign the VST tank so that it stays pressurized which keeps the boil point from dropping. Also, make it out of a plastic that doesn't absorb heat from the engine.

Speaking of keeping heat away from the tank. I finished my convert to 100% gasoline this weekend.

Here are the steps.

1. Cleaned the vst filter again, here is how you do it

http://www.simyamaha.com/category_s/1993.htm

2. Drained all fuel out of the fuel lines and disconnected the fuel lines from the gas tank (Very important)

3. Removed sending unit and got access to the tank (Keep fire exinguisher handy and a hose for safety).

4. I had already put the boat on the trailer and put an add on Craigs list asking people to come over and siphon 50 gallons of ethanol fuel away. I got 10 responses with an hour. Guy came over with 12 5 gallon cans and a hand pump. Just used the hand pump to get the siphon going and the fuel was all out. (Raise the bow up so it all drifts to the back of the tank).

4. Filled the 100 gallon tank with water and dawn detergent till it was over flowing which flushed out the remaing trace of gasoline out of the tank and any other deposits. Make sure you level lower the bow at first to fully fill the tank as it usually is mounted at an angle.

5. Siphoned out the tank again (Very quick with a garden hose) and raise the boat.

6. Pumped it full of water again and added a whole bottle of Salt-Away concentrate to the tank. Let it sit for an hour and then drained the tank again via the siphon. Lower then raise the boat to make sure it got into every part of the tank then out.

7. Pumped it full of water again and let overflow for a while to flush out the Salt-Away

8. Siphoned the tank out again

9. Hooked a wet dry vac up that was cleaned out on the inside to pump air into the tank for a vey hours intill I was sure that it was completely dry inside. I put the hose down the gas cap inlet and the air then came out the sending unit hole which is near the back of the tank.

10. While I was waiting for the tank to fill and drain, I finished cleaning the VST tank again. See my earlier posts for the directions. I then installed heat shielding on the back of the VST tank and on all the fuel lines I could get access to on the engine and the vst tank without taking them apart. I went to the local advanced auto parts store and bought some heat shield tape that is basically a foil cloth with a high temp adhesive. Clikc this link for the product I used which you can buy online
http://www.designengineering.com/catalog/design-engineering-inc/heat-sound-barrier

It reflects 400 degrees direct heat and 2000 degrees radiant heat an is very thin so you don't have to worry about clearance.

This stuff is easy to work with and I put it on anything carrying fuel that was facing or near the enigne including

1. Back of the VST Tank
2. VST tank Isolater plate
3. Fuel cooler attached to VST isolater plate
4. Fuel lines running from the gas filter in the front and along the engine area.

Pictures are below of the vst Tank


11. Went to West Marine and picked up a see through gas filter by Moeller and you can see it here. I added it ahead of the water separator filter so I can pick up any debris I knocked loose in the tank from cleaning it. It has a slick easy to change filter which only cost $10 for 3 of them an dthe filter itself is only $11. This is far less costly than replacing the new Water seperator filter.

http://www.westmarine.com/1/1/137-replacement-line-glass-view-fuel-filter.html


Interesting enough, the mesh filter on this looks finer than the one on the vst tank. So those that doubt that the ethanol fuel is boiling in the vst tank ask yourself how the fuel deposits get past 3 filters now that are finer than the vst screen.

12. Put the whole boat back together and drove it 20 miles to a marina in Cleveland (Lakeside) that only sell 100% gasoline they call clear fuel. Interestingly, the fuel does look a lot lighter in color and is almost clear compared with the more yellow tint in the ethanol. I also bought a tester to measure the ethanol content in a sample before I pumped in 100 gallons. It showed no ethanol in the fuel.

13. Added Startron and Ringfree to the 100 gallons of fuel

14. Put the boat in the water, ran for a few hours, burned 10 gallons, no drop in any rpm yet which suggests no problems with a clogged vst filter.

I have spoke to a couple of Yamaha dealers and they admit that their is a problem with the Yamaha engines not being able to avoid clogging while burning ethanol fuel. They are telling their customers no ethanol fuel period.