2007 f90 efi bad gas throughout the system

[adamant118]

this motor been instorage since 2013...
can someone explain step by step what to drain.

little background. back in 2013
liquid sea foam added to the fixed fuel tank with better then 1/2 of fuel # motor ran to get additive into system # fixed fuel tank drained as much i as i could back in 2013# small plastic fuel bowel drained#think i ran the motor out of fuel.
boat was put in storage from 2013 till today

today i
added 5 gal of fuel to tank
primed fuel bulb
would not start..

i drained the fuel rail ..all bad fuel
opened the little brass screw (dont know the name) and drained out of the little tube .. all bad gas.
pulled the injectors and dropped them off at the boat yard to be cleaned (supposed to be a small screen in them)

what else can i do?

[fairdeal]

btw Seafoam doesn't claim to be a gas stabilizer - but I suppose after 3 years wouldn't matter what you used...

well, assuming " small plastic fuel bowel drained, think i ran the motor out of fuel " is correct,
then all you had left in the engine was a little bit of fuel in the bottom of the VST
(which you drained today with " the little brass screw ...out of the little tube ")

and what was in the hoses/fuel rail to the injectors.

here's a suggestion, before you put the injectors back in:

- with "the little brass screw" open, use your primer bulb to pump a few ounces of fresh fuel through so that it drains out through "the little tube".

- next, close "the little brass screw" and fill the VST (until the bulb is hard). Then, put the fuel rail in a wide-mouth container to catch the gas, and turn "key on". The pump inside the VST should for a few seconds and pump fuel out through the rail. (don't let the pump run if it doesn't have fuel to pump).

That should minimize the chance of crapping up the injectors again; all I can think of without disassembling stuff.

[adamant118]

Then, put the fuel rail in a wide-mouth container to catch the gas, and turn "key on". The pump inside the VST should for a few seconds and pump fuel out through the rail. (don't let the pump run if it doesn't have fuel to pump).

That should minimize the chance of crapping up the injectors again; all I can think of without disassembling stuff.

with the injectors out and off the rail and fuel rail hanging i turned the key and did not find fuel coming out of the rail!

[fairdeal]

right, if there isn't fuel in the VST, there is nothing to pump.

That's why you first need to use the primer bulb to force the VST full

The high pressure pump inside the VST is not "self priming".

And, it is "cooled and lubricated" by the fuel it pumps, so it should not be run "dry"

Now, if you don't hear the faint "whir" of the pump running for a few seconds at key on,

you have another problem besides bad gas...

[cpostis]

with the injectors out and off the rail and fuel rail hanging i turned the key and did not find fuel coming out of the rail!

As others said, fill the VST tank first.
Did/do you hear/feel the fuel pump running when you first turned the key on?
Have you checked/replaced the VST filter?
6C5-13915-00-00 YAMAHA FILTER

[adamant118]

As others said, fill the VST tank first.
Did/do you hear/feel the fuel pump running when you first turned the key on?
Have you checked/replaced the VST filter?
6C5-13915-00-00 YAMAHA FILTER

When the key is turned on I can just hear a faint click

[cpostis]

When the key is turned on I can just hear a faint click

OK, the click is probably the relay. I would confirm/double check operation/non-operation of your fuel pump.

I am not familiar with F90, others that are should give you some advice. Maybe there is a fuse just for the pump? do you have voltage at the pump terminals when you first turn the key on?

Don't know if the following link pertains to your motor, but maybe it will help you.
http://www.simyamaha.com/category_s/1993.htm

Others, please?

[TownsendsFJR1300]

Did you close the VST drain and pump it full?

Did you THEN remove the fuel rail and turn the key on Momentarily?

Fuel should have shot out (not a lot but certainly visible).

And for NOW, get a separate fuel tank(portable) and run off of that.
You may very well be pumping 3 year old CONTAMINATED FUEL with your
new 5 gallons.. That ALONE will cause issues...

We can deal with flushing the tank fully later..

[rodbolt17]

does the HP pump run for 3-5 sec at key on?
if not remove it ,fill a small jar with Yamaha combustion chamber cleaner and soak it overnight,

clean the VST.
clean and flush all fuel lines.
send the injectors to flagship marine.
clean the fuel rail.

while waiting on the above go ahead and replace the water pump.
trust me it is bad now.

disassemble and rebuild the lift pump.

then it will run again.

[adamant118]

Thankyou for your help. Can someone walk me through the cleaning and removal vapor separator tank and fuel pump check? Thanks. I searched the net with no luck
__________________

[rodbolt17]

remove the intake,unpliug wireing and hoses as nessasary.
remove the VST.


on the fuel pump remove the inlet and outlet hoses remove the two bolts and it is off.
pump disassembly is covered in your service manual.

[cpostis]

I posted this earlier in your thread, Now this is for an F225. But it should show you kind of how to remove/service yours.

VST Removal, Cleaning, Filter/Screen Replacement

Do you have a service manual. If not you should invest in one.

[rodbolt17]

other than they both use electric pumps the VST in the F90 really shares nothing with the f225.

[cpostis]

other than they both use electric pumps the VST in the F90 really shares nothing with the f225.

Thanks Rodbolt,
Just a point of information to show what might be expected. I meant to say "kind of", not just "kind". I'll edit that.

He should get an appropriate manual. I know Yamaha manuals don't show too much detail on actual procedures. I have a Yam manual for mine, plus a Seloc, plus a Yamaha Marine Technical guide. The Seloc shows me more procedures than any Yam. I confirm specifications between Yam manuals and the Seloc. 99 % of the time time they concur.

[rodbolt17]

your right about the service manual.
it wont go into detail on VST removal step by step.
most manuals wont.
it takes about 1.5-2 hrs to do the F90.
when reassembling the VST you may find it easier to hold the tank in the left hand,hold the pump cover and isolator upside down in the other and place the tank on the upside down cover or the insulator tends to fall off.