Diagnosis help?

[Nautical]

2004 Yamaha F150.. Engine will speed up to 4400 rpms and will not go over 30mph.Stops at that range rpm and then starts to bog down slowly. When it hits 25 mph the engine will stabilize and level out . Will not accelerate ..The throttle is pinned .Not noticing any roughness and seems smooth at that level. I am thinking it is restriction somewhere on the low fuel side, or a bad fuel pump perhaps. Appreciate any thoughts /ideas.. Thanks

[rodbolt17]

my thought is a lack of fuel rail pressure.
this can be due to anything not allowing the VST to fill or the VST filter is clogged.

[Nautical]

my thought is a lack of fuel rail pressure.
this can be due to anything not allowing the VST to fill or the VST filter is clogged.

Thanks , makes sense..How about a coil going out ??I thought a possibility, but I agree thinking its fuel related .

[rodbolt17]

lose a coil and you typically lose 2 cylinders.

don't chase ghosties nor hunt bunnies bearing chocolates.

test the fuel rail pressure and go from there.

[Nautical]

Yep you are right about that ..start simple and work towards the issue..My mind has a tendency to wander sometimes..

[boscoe99]

Yep you are right about that ..start simple and work towards the issue..My mind has a tendency to wander sometimes..

Some minds wonder.

[99yam40]

I resemble that and might be offended

[RayBersch]

You know, ya just gotta keep up the reading of these posts to get the humor.

[boscoe99]

A mind can wonder as it wanders.

[rodbolt17]

it doesn't bother me much when my mind wanders.

its when its late getting back that I wonder.

[boscoe99]

I lost my mind a long time ago.

I wondered where it went.

I wandered around looking for it.

Never found it. Apparently it was not needed.

[Nautical]

OK checked the rail pressure and its 38 running 42 at rest This is at idle and revved up a bit 2300 rpms .. Working in a tank . Noticed a little black dry soot on couple of spark plugs. Wont go over 4200 rpms and not over 28 mph.. Noticed some fuel in the over flow vapor canister. Runs a little rough at idle , not perfectly smooth.. Any ideas ..appreciate Thx.

[rodbolt17]

Ideas?
yep you simply CANNOT test it on a flusher.
ALL rail pressure tests MUST be done at the failure RPM and load.

you should NEVER have liquid fuel in a charcoal canister.
this would indicate a VST needle leak or a stuck float.

[Nautical]

I just replaced the needle and seat last year.. Looks like this could be a yearly thing.. Maybe some dirt , but do you think this is the cause of lack of power (Roughness) at speed?Maybe the injectors need cleaning as well.I also noticed that overnight the rail pressure was at zero and the canister was full of fuel. Seems like the fuel rail is backfeeding fuel into the VST and out the overflow. Is there a check valve in this line .I don't see one.

[Nautical]

SOLVED !! I removed the fuel injectors and cleaned them ..One was spitting and not spraying.. After cleaning they were all spraying nicely.. Installed back in and the motor runs like a scalded dog.. Thanks and appreciate all the feedback and comments