2007 F250 wont go over 3400 RPM after long run

[SixelaRanger]

Looking for Help, after off shore run and returning back (15miles) once you goto idle and try to rethrottle motor won't go over 3400 RPM, the Yamaha Tech said the computer showed "low fuel pressure" he's changing the high pressure fuel pump today, already cleaned/changed filters VST & everywhere else... I'm concerned because you can get the boat on plane and it sputters and gets on plane if you put weight in front of boat. Also, once it totally cools down it runs normal? Seems like we are chasing ghost, any other opinion or confirmation related to high pressure fuel pump?

[rodbolt17]

my suggestion?
find a real tech.
no codes for low fuel pressure on the F250,Z 250 yes, F250 no.

[sailorboy]

same issue

Starting to have the Same problem here,
did not happen when "REAL TECH" from local shop took it out, engines are 2002 _F225's (WOOPS), this years service in the spring included complete VST rebuilds , maybe 150 hours so far, just started happening. I can turn the engine completely off and wait 5-10 seconds and it will respond properly.

have even have the engine "dropout" i suspect safe mode while running @ 4200

Just had "REAL TECH" replace the original oil pressure sending unit. (have the REALRECEIPT to prove it


Any ideas...

[sailorboy]

will try the swap fuel line.....
THANKS

[sailorboy]

well ....
we swapped the fuel lines at the fuel valve....
port/stb stb/port

started out and the engines ran great,,,
puttted around and then went to full throttle and the starboard engine (same one) stumbled and coughed ,, brought stb. engine to neutral,, switched off... switched on.. started ran great!!



whats next??

[sailorboy]

Ok,,, (this should really crank RodB)
for the sake of discussion ,, how many injectors are in a F225TXA, and average cost.

Is it rebuild-able, (spares)

is there any way to remove and check flow.

what controls the injector, is it something that can be benched checked?
thanks

[TownsendsFJR1300]

I don't know where you are location wise(if in the US or ?).

I can't post a link for some reason, but "Flag ship Marine" in Florida, (per RB) does all their injectors, cleaning, servicing, etc

[sailorboy]

Wben comming out of idle...and it starts to stumble I can shut off the engine wait 2-3 seconds and restart usually clears up...
Could the ECM be getting some sort of reset.

[rodbolt17]

go to the bank.
get 1500 dollars in quarters.
place them in a bucket.

stand 10 yds from the motor.
throw 2 handfuls at the motor.
retest.
repeat until it is fixed.

[rodbolt17]

to swap injectors on the F225 your looking at 4-5 hours labor.
would be cheaper to test rail pressure at the failure RPM and load.

I use flagship marine in punta gorda FL.

they will flow test them before and after cleaning and send back a report.

[sailorboy]

Ok... lots of bar talk , and this idea came out,
Supposedly there is a "check/bypass" valve of some type between the low pressure pump and the high pressure pump, that diverts the flow if the HP pump does not need it. I think i heard it was a spring activated type of device. OK... does this exist, what are it symptoms if it fails , how can it be tested?

[99yam40]

have you taken Rodbolts advice and test rail pressure at the failure RPM and load yet?

[fairdeal]

Ok... lots of bar talk , and this idea came out,
Supposedly there is a "check/bypass" valve of some type between the low pressure pump and the high pressure pump, that diverts the flow if the HP pump does not need it. I think i heard it was a spring activated type of device. OK... does this exist, what are it symptoms if it fails , how can it be tested?

the valve does indeed exist, on an F225 at least:




here's a link to a post on "testing:

http://www.yamahaoutboardparts.com/f...g-th27339.html

The significant observation being that although a small amount of air was passed below ~10 psi, it was only above that point that it fully "opened".

[rodbolt17]

about all the F250 and the F225 share is a Yamaha paint code.

the later 4.2L motors have the relief valve built into the VST.

a Yamaha is NOT a Yamaha.

not all motors share the same features.

they are EASY to test.

ya just have to understand the subsystems,how they work together AND buy a few tools.

[sailorboy]

99YAM...
no not yet, the boat is several hours away and trying to coordinate schedules w/ the "REAL mechanic" is a bit difficult....
hopefully we will have a arsenal of items to test...

Rod..
"later 4.2..." what year did this change happen. I had the VST's rebuilt at the beginning of the season and the mechanic was amazed that a lot of the parts did not look correct.. the motors in their early life had limited TLC