2004 Yam 150 4 stroke problem

[rodbolt17]

usually.
but let them dry.
take a good light and look down the line.
if you see a layer of brownish dust clean them or replace them.

[flatbottom]

Thanks rodbolt.

In your previous psot, just above my last one, what do you mean when you say:

as it is such an old motor it is unlikely the latest link and sync has been done.

Are you talking about the throttle plates being in sync? Injectors?

It does stumble at idle and above idle but it never recovers to where it runs on all four, smoothly, at any throttle setting.

Thanks again,

Scott

[boscoe99]

The original sync and link for your model had the throttle plates being fully closed when at idle. All of the air flowed through the idle air control valve. Yamaha published a new procedure whereby the throttle plates are cracked open a tad, allowing some air to flow through, with the remainder of the air flowing through the idle air control valve, albeit at a diminished rate.

[TownsendsFJR1300]

I have the PDF for the procedure if you need it. PM me with a reg e-mail address and I'll send it to you.

Please mention in the header F150 SYNC..

[flatbottom]

Cant hurt to have it, PM on the way.

Thanks,


Scott

[rodbolt17]

there are actually two newer methods.
there is a tech bulliten on it.
but basically what Boscoe said.
while a laptop with YDS and a tech-mate vacuum mate makes it go easier.
I had to do my 07 F150 back in 07 way before Yamaha came out with any words about it.
something about maneuvering around my dock aand the motor stumble and stall and that annoying stall alarm that alerted all my neighbors that my motor just stalled.

this while wearing a Yamaha master tech ball cap.

my first attempt was successful but took me about 6 hours.
only tools I had was the one between my ears, a multimeter and some paper clips.
my procedure was basically increase the idle speed using the idle speed screw.
I think I opened it to a TPS reading of about .8V.
then I loosened the TPS and moved it to a value of about .7V.
I had to play a bit.
but when I was done I had a stable idle at about 700 RPM and no more stumble/stall at low speed throttle movements.
took it to the shop and recorded an ISC request of about 40%.
the original setting had it at 60-65%.
I showed the other techs at the shop how to do it.
that was about 3 yrs before any words from Yamaha but most 09 and older F150 motors suffered from this stumble/stall until the sync was redone.

now this procedure is only done AFTER the motor is running correctly. it wont help anything but the annoying stumble/stall just off idle.

I think a guy named High Sierra had an issue that I beat on for days until someone did it.

[TownsendsFJR1300]

You have mail Flatbottom!

And RB, I saved the latest one that was posted here (maybe 6 months ago?) I believe either you or Boscoe posted it...

This one starts on page 6-25 to 8-28 (Yamaha shop manual) also using the YDS

I haven't seen it posted again since then (un-less there's another updated version)

[flatbottom]

Thanks for every ones help.

I finally finished the fuel system rebuild, everything from new fuel tank, lines, VST tank rebuild, all new filters, lift pumps, rebuilt and flow tested injectors, (off ebay, w/ flow sheet) flushed and blew everything out, really anal overkill here. I left not one stone unturned in the fuel system.

Took it out today and tried to run it. At least I can get it almost on plane now but I have a problem with #1 cylinder, it wont fire. The plug stays wet, I tried switching plugs with #2 and 2 runs ok, #1 wont fire, wet plug. Tried switching wires, same thing.

At this point, I am thinking either there is a stuck cylinder head valve (compression test is next) or #1 injector is leaking down and flooding the cylinder. I can see a sheen on the water so I know raw fuel is being blown out the exhaust, most likely from #1.

When I was pulling plug wire while it was running and pulling # 1 made no difference (how I tracked it down) I noticed that the spark was quite strong and would jump an inch or so, same from the other coil that fires #2. So I believe I can rule the coil and wires out.

If the compression test comes back ok (pretty sure it will) I am trying to figure out which way to turn next.

When I put the new external 10 (or was it 5) micron filter and water separator on, with the new pump bulb and lines, I pumped it up pretty strong and bled the VCT again to make sure no water had made it in somehow. Hope I didn't fill # 1 with fuel doing this, assuming a leaking injector.

I ran it hard trying to figure things out while troubleshooting but realized I was washing a cylinder down, so I quit and brought it home.

At least the thing now runs on 3 cylinders, where it was only running on maybe 1 before, maybe 1500rpm (see first post, it was terrible and where I am at now is a huge improvement, up to around 5000 rpm but I can tell it still isn't right when it idles, I can "feel it" and feel it up to around 2500rpm. (seems like baby steps here)

After the compression test, I was going to try swapping injectors, putting it on muffs and see what happens to the cylinder that gets the suspect #1 injector, I think I can now tell at idle if its still missing, not to mention pulling wires again to test.

Sorry for the long post, just don't want to mess anything up since coming this far.

Any other suggestions on which way to turn next here?

[fairdeal]

After the compression test,

a compression check - and leakdown test - would be very good information to have before you go any further....

[flatbottom]

Turns out it was the injector freely spraying gas into the cylinder and flooding it out.

Hope I didn't damage the cyl/rings as I ran the thing pretty hard 5 or 6 times for 30 seconds or so at full tilt, not to mention idleing around for a little bit trying to suss tings out.

Need to change the oil now...

[fairdeal]

rebuilt and flow tested injectors, (off ebay, w/ flow sheet)

Turns out it was the injector freely spraying gas into the cylinder and flooding it out.

well that sux...

[flatbottom]

Came with flow sheets, a pretty reputable guy from feedback. Shipped a replacement yesterday. We shall see. KM Racing.

Nothings a slam dunk anymore...

4x Marine Yamaha F150 Outboard Four Stroke Fuel Injectors: Flow Tested & Cleaned | eBay