Yamahas F300 BETO Fuel Pump

[rodbolt17]

your simply not getting it.
if the VST prefilter isn't clogged its not the LP.
when you cleaned the VST did you clean the injector screens as well ?
once the LP pump feeds the fuel to the vst it can only leave one way. via the injectors.
however what is not immediately used by the injectors is returned to the VST and reused.
carefully study the flow diagram boscoe posted and you will see it.

unpon leaving the HP outlet fuel can take two paths.
1 is to the rail for immediate use.
2 is out the pressure regulator to be returned to the VST.

is it possible the pump motor brushes are failing? could be.
the pump has two separate parts.
1 is the pump rotor assy the other is the pump motor.
both are encased in a single body.

[captain rednut]

fuel pump

thanks for your reply rodbolt.
regards cr

[captain rednut]

cleaned injector screens and still fails

hi
i have taken all the advice given and replaced filter screens and had the injectors cleaned and flowed professionally and still i only get 100 ltrs of fuel use and the HP filter cloggs with black dust again???????
im hoping you can assist with any more suggestions before i replace the pumps and im still shadowed with doubt??
regards CR

[rodbolt17]

it seems you may have either brushes that are failing or a fuel line that is failing.

if you do replace the pump, save the old one.
let it dry a few days and cut it open carefully.
its kinda scary.

[captain rednut]

injectors

hi Rodbolt
just for a matter of interest this model has no filter baskets or screens in the injectors. Strange but true.
i cut open my pumps to find the brushs failed which at least now i know the cause.
just the big wait now for parts.
regards cr

[99yam40]

can you post a pic of the failed pump motor/brushes
would be interesting to see for me and others

I wonder if someone left the injector screens out for some reason?

[captain rednut]

filter screens

hi the injectors are original as i UN-packed the new engine from the crate upon installation and this is the first time they have been apart, the injector repairers over here said there is no facility for one in there design. (interesting)
i can find any spare part list for injectors to see if they show them?? but just new replacement only.
regards cr

[Underwaterdogg]

What happened?

Rednut,

I have exactly the same issue on one of my F300XCA's. How did you end up solving the problem?

I took apart my VST tank to find a badly corroded HP pump leaving the VST tank full of rust and black dust from somewhere, I am assuming from the HP pump or the return fuel line. Photos attached. If you are still around any info on how you solved for it would be greatly appreciated.

Thanks,
Steven
32' twin vee center console w/ twin yamaha F300's

[rodbolt17]

and that is from a meticulously well maintained rig.
NOT.

[Underwaterdogg]

and that is from a meticulously well maintained rig.
NOT.

No it is NOT. Thank you for your profundities, lol. I bought the boat used in Louisiana and it could have sat with some E10 in it for a while. The stuff is pretty brutal on equipment if it sits and separates. That may have contributed to the corrosion and possibly the pump failing but I think that the black dust that is causing the HP pump filter to clog is coming from the pump internals deteriorating and returning to the tank via the return line. I am going to check the injector screens tomorrow to verify. I took the inspection plate off of the back of the VST where the little heat exchanger is and it was a bit clogged, water still could get through but I'm sure cooling was affected. So the pump could have been getting warm and deteriorating, or it was ethanol, or they just fall apart on their own...hopefully not, since they are a 300.00 part and about 2hrs to change. Will definitely drain the VST tank or flush with race gas if the boat is ever going to sit for very long again, but i doubt it will

[captain rednut]

Fuel Pump

Hey UnderwaterDog
That certainly looks like ethanol damage to me?? and my low pressure pump was where my black dust was coming from and i would highly recommend you change both of your pumps.
Cheers JIM

[Underwaterdogg]

Hey UnderwaterDog
That certainly looks like ethanol damage to me?? and my low pressure pump was where my black dust was coming from and i would highly recommend you change both of your pumps.
Cheers JIM

Was your inlet filter into the VST tank plugged with stuff from the LP pump?

Thanks!

[Grady-Gator]

it seems you may have either brushes that are failing or a fuel line that is failing.

if you do replace the pump, save the old one.
let it dry a few days and cut it open carefully.
its kinda scary.

Rodbolt,
On my F300 (480 hours) the screen into the top VST tank is clean, but the VST filter on the high pressure pump continues to get clogged with dust from the pump brushes. My mechanic believes that the high pressure pump has failed and has replaced it, and that the low pressure pump is fine since the inlet screen to the VST looks clean. Does this seem correct to you? I have put about another 30 gallons of fuel through the VST so far and no additional problems. However, I have not opened up the VST tank to see if the HP screen is getting clogged again. Also, is it reasonable for the HP pump to fail at this many hours, or is it possible that there are is another problem, such as the VST cooling not working properly?
Thanks