VST Filter... Am I the only one having trouble???

[reefman]

I'm running a 2002 ox66 150 hp which I bought last year. Replaced the VST twice last year and will be doing it again after work tonight. I've put 148 hours on since buying the boat. (410 total hours) I've been using the Yamaha water separator ( 2 per season ) and replaced the filter element from the small fuel filter on the engine each season. I use Valvtect for ethanol treatment and ring free as well. I never thought replacing the VST filter would become a seasonal maintenance item. Is anyone else going thru these things at this pace? Is it a function of where I'm buying my fuel? Would love to hear from others if you're having similar issues or not.

 

[TimC2520]

I do mine once a year, haven't had a problem.

 

[Bryan 2530]

Probably the ethanol cleaning out the tank.

What year is the tank, has it sat for a while?

 

[TomS]

Why are you replacing the filters and not just cleaning them?

I just use a can of spray carb cleaner with the little hose attached and blast it into the top of the filter, then spin the base to clean each section of the 'pie'.

Are they all gunked up when you open them up? Fine gray powder or something else?

-- Tom

 

[Capt Bill Welder]

I still have an OX66 200 HP.
I replace the racor every 50 hours
VST Has never looked bad. I clean the VST tank and VST filter every 400 hours anyway

I have NEVER used ethanol. The two marinas where I buy fuel have newer tanks.

Not many hours on your motor. Sometimes that is not as good as a motor that has been used regularly.

IMO
If it were me I would have the fuel tank cleaned by a pro. Buy fuel from only one source that has newer tanks. If you are vigilant about your changing racor filters, have a clean fuel tank and get fuel from a quality vendor. You should be able to get 1200+ hours from a VST filter before replacing.

 

[inTherapy]

I do not know a hpdi owner that has not had ethonal issues, particularly the vst filter. You can clean your tank until your fingers fall off, you will still have a problem. As inconvenient as it is, add it to your maintenance schedule. I just did mine again this season at 80 hours and they wear so/so. I can do twins in about an hour and a half.

 

[dream catcher]

I have a 2002 225 OX66 and I have constant VST problems, I have it changed at least once a year and probably more than once a few times. I have never done it myself as I don't know that much about engines and didn't want to paly with it, however, i might try it soon. I just recently changed my fuel/water seperator to a 2 micron and I thought that would solve the problem, it was working fine until yesterday when she started bogging down like she has done many other times, which turned out to be the VST on most occasions, I have been seriously considering re-powering with a new engine, it is just too expensive and too much of a hassle to keep dealing with this problem!!!! So short answer, no you are not the only one.

 

[TomS]

One thing to remember is that the VST filter is just a filter.. it is not the source of the problem, just a symptom.

If it is getting clogged, then something isn't right in your fuel system. Either you have some bad gasoline, your fuel tank is dirty, your fuel lines are deteriorating, etc.. The VST is the next to last filter before the fuel hits your injectors, and is much easier to get to and service than the injector filters.

But if you are having frequent problems where the VST filter needs to be replaced/cleaned more than once a season, you probably want to go in and check your injector filters as well. If the injector filters are clogged you will see some of the same performance problems, regardless of how clean the VST filter is.

Post pics of what the clogged VST filter looks like if you can, or at least describe what is clogging the filter.. ie is it black specks (deteriorating fuel line), brown crud (tank deposits being 'cleaned' by Ethanol), white gel (old or bad gas, possibly a mix of MTBE and Ethanol) or a fine gray powder (the mystery powder, some say is from the VST tank, others think is a byproduct of Ethanol fuel added during processing/transport)

-- Tom

 

[reefman]

I'm in the fine gray powder camp. My tank is spotless, no debris at all.

 

[dream catcher]

mine also is the white/gray very fine powder. I have never had the tank cleaned as I have been told that there is no real good way to clean it and in addition that the powder will probably come back after it reacts with the tank? I don't know how true this is, but I have never tried it? I have been told that the only real way to solve it is to replace the tank, I have been avoiding that as i really don't want to cut up the deck, but i have to do something, either try a new tank or a new motor or both???

 

[Brent]

The last item left is the injectors
Has injectors been serviced at a FI service center and the FI filters changed?
These filters are very small and fit inside the FI

 

[Striperswiper]

I have a 1999 225 OX66 and had tons of problems with the fuel system.

I installed a 10 micron Racor filter with a drain on it and change it out roughly 50 hours.

I cleaned the VST filter, pulled the fuel rail and cleaned the filters on the injectors ( pretty easy job).

Then I found the problem in the fuel tank, the previous owner dropped 3 of the metal seal tabs on the fuel additive bottles into the tank while putting in the additive.

The engine would run fine then suck one of the tabs onto the end of the pickup tube in the tank and the motor would stall out.

I got them out of the tank through the fuel gauge sending unit hole with a spring loaded grabber tool.

There is also a very small screen about the size of a dime in the top half of the VST tank by the pressure regulator that needs to be cleaned. It's behind the regulator and the first time I tried to locate it I couldn't . It there, very small and was over 2/3 clogged.

One other unrelated thing you should be aware of is that the mechanical fuel pumps have to be replaced every 2 years. If you don't and the diaphrams rip and dump raw fuel into the engine crankcase you can kiss your engine goodbye.

Capt Brian

 

[TomS]

Good info Capt. Brian.

I forgot about that last dime-sized filter, its the pressure regulator filter if anyone is looking for it. I believe it is mounted in the top of the VST tank where the return line comes in from the fuel rail. Easy to get to and clean once you know where it is, its shaped like a small thimble.

-- Tom

 

[Pain Management]

Tom,

Do you have a picture of where this small filter is?

 

[TomS]

This is the parts diagram for my 1999 SX200TXRX.

The small filter is part #13.

It is accessed by removing the two bolts (#16) from the pressure regulator (#18) on the backside of the top of the VST tank assembly.

FYI, parts diagrams for all Yamaha motors are here:

http://www.boats.net/parts/search/Yamah ... parts.html

The diagram above is from the "Fuel Injection Pump" page.

-- Tom

 

[Pain Management]

Once again Tom comes through... Thanks

 

[SBH2OMan]

By the way, be careful when ordering replacement parts. It appears that there are variations on the fuel injection pump/float assembly that can lead you to getting the WRONG parts. I don't know if this is just a 1999 problem with the S250TXRX, but there are two distinct variations - one is the 65L which uses a blue VST filter and the 66K variation which has a clear one without side panels (it will appear tan when removed).

I just spent over $100 on parts and an hour of my time to remove and replace the VST filter, only to find that SIM Yamaha sent me the "wrong" parts (their schematic probably shows it being the right one).


For an example of what I am talking about you can see the differences here:

66K variant:
http://parts.yamaha-motor.com/?ls=outboard
(you'll have to navigate to the 1999 S250 TXRX and select "Fuel Injection Pump"

65L Variant (more expensive - about double the price of the 66K filter:
http://www.boats.net/parts/search/Yamah ... parts.html

 

[Parker23]

I have a 2002 225 OX66 and I have constant VST problems, I have it changed at least once a year and probably more than once a few times. I have never done it myself as I don't know that much about engines and didn't want to paly with it, however, i might try it soon. I just recently changed my fuel/water seperator to a 2 micron and I thought that would solve the problem, it was working fine until yesterday when she started bogging down like she has done many other times, which turned out to be the VST on most occasions, I have been seriously considering re-powering with a new engine, it is just too expensive and too much of a hassle to keep dealing with this problem!!!! So short answer, no you are not the only one.

What was the outcome? Was it the VST? I also installed a 2 micron seperator. Thanks Frank