F225 TXRC bogging down - fuel rail pressure question

[pstephens46]

With respect to TOS, a moderator sent me a PM and thanked me for not responding to some apparent insults posted by another forum member. I did not see the insulting posts. Appears the moderator might have removed them.

It is a zoo over there. I kind of enjoy it is a perverse sort of way. I like stirring some of those folks up. Seems that you take a bit of pleasure as well.

fairdeal stays above the fray.

I get so confused with all the tubes around the VST. I couldn't remember if the "F filter" was after or before the HP pump. If after, I liked the idea of a clear replaceable filter. If it could handle pressure I suppose.

The Hull Truth. The simplest questions by OPs become just a muckfest. "My Seastar seals are leaking". Then we are off and running....

Yes it's fun to poke sometimes.

[walleye1]

The Hull Truth?

[boscoe99]

Where is the F filter located in this diagram?

With respect to TOS, a moderator sent me a PM and thanked me for not responding to some apparent insults posted by another forum member. I did not see the insulting posts. Appears the moderator might have removed them.

It is a zoo over there. I kind of enjoy it is a perverse sort of way. I like stirring some of those folks up. Seems that you take a bit of pleasure as well.

fairdeal stays above the fray.

[fairdeal]

it would be the filter immediately before the float chamber

although given the box surrounding several parts,
that schematic may represent a later version where filter, check valve, etc are actually "in the VST"

[pstephens46]

In most Yams the VST is vented to the atmosphere via the charcoal cannister in the vapor recovery system.

I seem to recall some early models not using the vapor recovery system simply vented the VST directly to the atmosphere.

Where is the F filter located in this diagram?

[fairdeal]

A competent engineer who thought for ten minutes about maintenance could have come up with a better idea than burying the VST.

Agree. IMO, I don't think the engineers concluded that the VST was to be serviced as much as this forum indicates it is.

"Fuel System Components" would be an especially fascinating chapter in the book Inside Stories of the Yamaha Engineering Dept that I would love to read..

The decision to use a pencil-eraser sized VST screen in the early 3.3 is particularly baffling; not surprisingly eventually that grows substantially.

also interesting, I believe over subsequent years the "F-filter", "check valve", fuel cooler (and pressure regulator?) transition from separate pieces plumbed around the engine, to simply integrated into the VST itself

[pstephens46]

One potential source (I read about this on another forum) is the HP pump itself. Moisture contained within the hygroscopic ethanol rusts the internal metal components of the Hi PSI pump. As I understand it, you don't need suspended, free water in the fuel, just moisture contained within the E10. That moisture corrodes the pumps internals which then get pumped out to the injectors. The fuel returned to the VST from the fuel injector supply loop - (wrong nomenclature I'm sure, but you get the idea) contains these ruts bits along with the little bits of crap sloughed off by the internal degradation of the fuel hose. There is a vendor who sells a replacement pump which contains zero metal. Supposedly its got ceramic guts. I cannot vouch for it.

One guy actually cut an old HP pump open and discovered it rusting out internally. So, you can change all the filters short of the VST all you want, but you still can't prevent detritus from gumming up the VST fuel pump filter or the injector screens. At least, this is how it appears to me.

On my boat, the external Racor was completely clean. The first stage YAM filter was fine. Yet there was crap in the VST screen. I did not cut open the F filter, I just tossed and replaced it. Another 30 dollar bill.

I am giving consideration to adding a simple glass see-through in place of the F filter. If I can relocate it to a more sensible location I will.

I like this F filter idea.

[oldmako69]

One potential source (I read about this on another forum) is the HP pump itself. Moisture contained within the hygroscopic ethanol rusts the internal metal components of the Hi PSI pump. As I understand it, you don't need suspended, free water in the fuel, just moisture contained within the E10. That moisture corrodes the pumps internals which then get pumped out to the injectors. The fuel returned to the VST from the fuel injector supply loop - (wrong nomenclature I'm sure, but you get the idea) contains these ruts bits along with the little bits of crap sloughed off by the internal degradation of the fuel hose. There is a vendor who sells a replacement pump which contains zero metal. Supposedly its got ceramic guts. I cannot vouch for it.

One guy actually cut an old HP pump open and discovered it rusting out internally. So, you can change all the filters short of the VST all you want, but you still can't prevent detritus from gumming up the VST fuel pump filter or the injector screens. At least, this is how it appears to me.

On my boat, the external Racor was completely clean. The first stage YAM filter was fine. Yet there was crap in the VST screen. I did not cut open the F filter, I just tossed and replaced it. Another 30 dollar bill.

I am giving consideration to adding a simple glass see-through in place of the F filter. If I can relocate it to a more sensible location I will.

[Crazy Train]

Oh come on. All of this is so simple!!

A clogged VST pump screen needs to be removed to be cleaned. The particulates found their way into the VST and wound up clogging the intake screen. Simply dislodging them just kicks the can down the road because it doesn't take them out of the VST. They'll just slosh around until they get sucked into the screen. You know the one with the huge surface area. Its massive and takes TONS of material before it....well, let's just say that without perfectly clean fuel that it clogs right off the bat. Removing the VST is a pain in the ass primarily because of the way they designed it. Thirty five bucks for a HP pump filter / screen. I't a 29 cent piece of plastic with a screen 3/8 inch across. A competent engineer who thought for ten minutes about maintenance could have come up with a better idea than burying the VST. Or at least, an easier method to service it and the 20 dollar gasket on the VST. On my port engine, its not too terrible, but on the starboard it sucks.

Amazingly, my engines are treating me great. But, last year was another matter. Its a shame because they really are nice when spooled up.

Agree. IMO, I don't think the engineers concluded that the VST was to be serviced as much as this forum indicates it is. I believe they assigned their filtering requirements to the on-board filter and called it good to go. The VST speaks to non-serviceability (hidden, tiny weak screws, internal filter, non-friendly gasket, etc.) except for the drain to winterize the VST. It was not meant to be/thought to be needed to be cracked open for frequent filter changes. But here we are. So where does all that particulate matter come from to clog the HP pump filter if all that gas just passed through the on-board fuel pump? Is it the brush dust that RODBOLT speaks to? Is it enthanol eating away fuel lines and fittings? All of the above?

[oldmako69]

My HP pump filter is offset to the right and has a cover over it as shown in Townsend's diagram, so I am not sure if the carb cleaner coming out of the straw would hit it. I intend to pull/open the VST to inspect the filter....and get to the fuel injectors since that is where the diagnosis is pointing me. Your maintenance rigor sounds like it is paying off. This forum is littered with folks that have fuel system issues. I just changed the LP pump 'check valve' last season. I believe one of the regular contributors on this forum commented that fuel system issues are the number 1 Yamaha maintenance issue, if I recall correctly. If true, it is sad.

Oh come on. All of this is so simple!!

A clogged VST pump screen needs to be removed to be cleaned. The particulates found their way into the VST and wound up clogging the intake screen. Simply dislodging them just kicks the can down the road because it doesn't take them out of the VST. They'll just slosh around until they get sucked into the screen. You know the one with the huge surface area. Its massive and takes TONS of material before it....well, let's just say that without perfectly clean fuel that it clogs right off the bat. Removing the VST is a pain in the ass primarily because of the way they designed it. Thirty five bucks for a HP pump filter / screen. I't a 29 cent piece of plastic with a screen 3/8 inch across. A competent engineer who thought for ten minutes about maintenance could have come up with a better idea than burying the VST. Or at least, an easier method to service it and the 20 dollar gasket on the VST. On my port engine, its not too terrible, but on the starboard it sucks.

Amazingly, my engines are treating me great. But, last year was another matter. Its a shame because they really are nice when spooled up.

[oldmako69]

But then they'd have even more trouble justifying their prices.

[boscoe99]

Extra electronics for brushless, prone to failure if brushless motor gets jammed.
You're right though more modern motor control solutions out there, look at modern inverter airconditioners.

The outboard motor world is years, if not decades of years, behind the automotive world. We customers/users pay the price.

It is not as if the outboard motor makers need to invent a wheel. All they really have to do is copy the best of what the auto world has to offer.

[Crazy Train]

Once the VST is clean, you shouldn't have to go in there again (any time soon) with proper filter changes, etc...

I've never changed /checked the VST filter on my engine (original owner) but I keep after exterior filters, drain the VST on occasion and use fuel additives (Non-ethanol fuel too).

BTW, it has been mentioned in previous posts you can spray carb cleaner up the drain in the VST. Wether the spray would actually hit the filter, dunno for your engine. Probably couldn't hurt(and easy too).

.

My HP pump filter is offset to the right and has a cover over it as shown in Townsend's diagram, so I am not sure if the carb cleaner coming out of the straw would hit it. I intend to pull/open the VST to inspect the filter....and get to the fuel injectors since that is where the diagnosis is pointing me. Your maintenance rigor sounds like it is paying off. This forum is littered with folks that have fuel system issues. I just changed the LP pump 'check valve' last season. I believe one of the regular contributors on this forum commented that fuel system issues are the number 1 Yamaha maintenance issue, if I recall correctly. If true, it is sad.

[zenoahphobic]

Which raises the question, why not use a brushless DC motor?

Better reliability. Less maintenance costs. Less profit for dealer mokanics.

Oh, while they are at it, make the lift pump motor variable speed so that it does not have to over work and heat up the gasoline any more than necessary. Take out the crap return lines and expensive pressure relief valve that fails and makes everyone go crazy.

Extra electronics for brushless, prone to failure if brushless motor gets jammed.
You're right though more modern motor control solutions out there, look at modern inverter airconditioners.

[Crazy Train]

In most Yams the VST is vented to the atmosphere via the charcoal cannister in the vapor recovery system.

I seem to recall some early models not using the vapor recovery system simply vented the VST directly to the atmosphere.

This is a great block diagram..thanks Boscoe.