Yamahas F300 BETO Fuel Pump

[captain rednut]

Hi has anyone had trouble with the high pressure fuel pump on a F300 V6
engine??? mine is 18 months old and has done 500 hrs, it has always had Quality 98 Ron fuel with no water or ethanol blends anywhere near it.
the fuel pressure is a maximum of 30psi and drops to 22 psi.
im going to test the fuel pressure regulator to see if its a possible cause to the lack of power, the engine only idles in gear and if i accelerate it drops away until it misses and stops completely.
any thoughts and ideas or am i on the right track with a new H/P fuel pump??
Thanks CR

[rodbolt17]

I would suspect a clogged filter long before suspecting a defective pump.

[boscoe99]

Nominal HP pump output is 47.9 psi when the key is first turned on with the motor not running.

With the motor started the output will drop to nominally 40.6 psi at 700 RPM.

With 500 hours time on the motor, when were the filters last changed? If never, they are long over due.

Yamaha recommends checking (and replacing if necessary) the fuel pumps at 300 hours. Check the HP pump after the filters have been replaced if you still do not have rated pressure.

Here is a diagram showing the two that are not so obvious as the primary fuel filter:

[rodbolt17]

500 hours and no professional maint.
dog it till its dead and blame Yamaha.

never heard of a recommendation to check/change fuel pumps.
there are recommended hourly AND calander checks recommended.

as both pumps are blow through style pumps you can and will accumulate brush dust from the pump motors.
this dust can and will clog filters including the injector screens.

typically I remove and spray out the injectors when servicing the VST filters.

its called routine maint.
routine maint is ALWAYS less costly than corrective maint.

[boscoe99]

From the Yamaha V6 F225/F250/F300 Offshore Service Manual

[boscoe99]

Capt Solo, I think you have F225TXR(X)s. These don't use an oil control valve. Only the motors with a variable cam timing mechanism have an OCV.

Many, many different Yams have different features. What one has another does not necessarily have. That is why it is important to know the precise model identity of the motor. Hell, many won't even say if they have a two stroke or a four stroke. Maybe they don't even know the difference.

[captain rednut]

fuel pump

hi guys thank very much for your advice and i will follow all recommendations, i will let you know how i get on and i find it interesting that Yamaha recommend changing the pump at 300hrs that makes it very expensive boating especially the costs of parts in Australia.
cheers cr

[boscoe99]

The recommendation is to check the pump and then only replace it if necessary. Kinda strange because if it was really necessary the pump would have/should have cause a running issue before the inspection interval came due.

I don't think Yamaha really thinks through some of the stuff they publish.

[rodbolt17]

thought that was deleted.
we asked about pump thing in class 4 yrs or so ago.
we were told it was a translator error.
kinda like some manuals and at least 1 tech guide referred to the motor running a fever to describe an overheat.
its a jinglish thing that most techs are not used to. way better than what it was and some better than the early Volvo manuals.

300 hours on checking/cleaning/replacing the VST filters is rather optimistic.
you wont believe the amount of errors in the tune-up spec guides over the years.
pick up the 84-2005 guide.
look on pages 198-200 for an example.
as a trained tech knowing how and why things work its easy to spot the typo.

[boscoe99]

thought that was deleted.
we asked about pump thing in class 4 yrs or so ago.
we were told it was a translator error.
kinda like some manuals and at least 1 tech guide referred to the motor running a fever to describe an overheat.
its a jinglish thing that most techs are not used to. way better than what it was and some better than the early Volvo manuals.

300 hours on checking/cleaning/replacing the VST filters is rather optimistic.
you wont believe the amount of errors in the tune-up spec guides over the years.
pick up the 84-2005 guide.
look on pages 198-200 for an example.
as a trained tech knowing how and why things work its easy to spot the typo.

The part that is most disappointing is that Yamaha will not correct bad data. When was the last time a service manual revision was ever issued? I have never seen one. Oh, I have seen a supplement or two but that is about it. And maybe an obscure technical bulletin that consumers, who have service manuals, most likely will never see. And then there are some internal bulletins that Yamaha dealers never get to see. Hey, if a problem is not known to the world it must not exist.

I found a problem in my Mercury manual and called Merc about it. They informed me that a revision had been issued for my manual. They sent me another copy.

In the airline world the operators are continually feeding information back to the manufacturers. Suggestions, corrections, what have you. The manufacturers review that data and based upon their findings continue to update all of the documents that are related to the product in question. The marine world needs to come into the 20th century. Oh wait, we are now in the 21st century.

[rodbolt17]

years ago we actually did get paste in copies of tech info that was incorrect in the manual.
I have not seen one in sometime now.

some of the tune-up spec guides are still wrong.

funniest tech revision was about 2002 when the HPDI TPS adjustment asked for a voltage check orange to black. tech bulliten said 12V.
if you ever have 12V orange to black stop adjusting and fix it.

if ya get a chance post what that typo is on the referenced pages.

[captain rednut]

Problem Found

Hey Rodbolt
You were spot on with your suggestion the high pressure pump filter is blocked with the black carbon sludge, can you help me understand why the low pressure filter screen is like brand new and only the H/P screen is blocked??.
There was no other debris or water/anything found except the black sludge on the screen only.
how do i prevent the sludge from occurring as i reckon it is happening hundreds of hours ago as Ive slowly had slower top end rpm for a while.
its interesting that Yamaha Australia don't have stocks of either high or low filter screens.
What is the black sludge ?? you mention its from the pumps??
i appreciate your help.
regards CR

[rodbolt17]

its brush dust.
like I said, its a blow through pump.
gasoline flows over the armature windings, across the brushes and out the outlet.

I would remove and spray out the injector filters as well.
if you did not damage the LP and HP filters clean them and reuse them.

[captain rednut]

fuel pump

hi Rodbolt Thank you very much for your assistance and i must be unlucky having so much carbon so quickly with this engine as this is my third big four stroke yamaha with big hours and i have never had this happen before, i know of a heap of commercial guys who have 250hp yamaha 2012 model with 3000 hrs and they have never had there fuel system apart which makes me wonder why mine has experienced this problem so early?? maybe the 300hp pump design are more prone to this??
thanks again for your help.
regards CR

[captain rednut]

Black Dust Syptoms Back Again

hi Rodbolt
After i cleaned the high pressure pump filter screen i re-assembled it all for a sea trial and it went well for half a day about a 100 ltrs of fuel used and back to the same symptoms again so im assuming they are blocked again??
im going to strip it again today, so to avoid this from happening again do i replace the low pressure pump as it must be where the dust comes from to block the high pressure pre-filter.?? there are no low or high pressure pumps or filter screens ever sold or stocked in australia which makes this a long wait for a cure.
i cant find anyone here in Australia that has ever heard about this and im desperate to find a cure as where we fish is dangerous every time this happens.
Regards CR