225 dieing

[Highmark]

Here is what she is doing. after start up and warm up.
The idle will fall off till it dies.
I had it in to a shop, They said the injectors needed cleaning and that was the problem.
But this weekend out chasing tuna. It was doing the same thing.
Pull the throttol lever back to in gear idle and it would idle along then would idle up a grand then start
dropping off till it died..

Now if I shut it off then restarted it would idle fine. Right at 8 grand .
but after running at like 14 to 18 hundred and pulling it back to in gear idle it starts this again..
what ever was needed to run at 6 to 8 mph.

All the filters are clean and good gas, new plugs. The engine runs good
execpt for the dieing thing.. after they did the injectors cleaning. my mileage is up. and
throttle response is good. Engine is a 2005 model with 570 hrs on it.. always serviced

[mygrady1]

Trust me... With this crowd you better give a model#

[rodbolt17]

I would check the lift pump relief valve LONG before I suspected an injector.
I work with techs that cannot tell you OR me why that valve is there.
do you know why?

[Highmark]

Where is it located and how do I check it ?

I would check the lift pump relief valve LONG before I suspected an injector.
I work with techs that cannot tell you OR me why that valve is there.
do you know why?

http://cdn.boats.net/diagram/yamaha/...ION_PUMP_1.png

would be item 40 on the diagram ?

[TownsendsFJR1300]

Trust me... With this crowd you better give a model#

He's got the model # up top in the upper header..

__________________________________________________ _______________

I would check the lift pump relief valve LONG before I suspected an injector.
I work with techs that cannot tell you OR me why that valve is there.
do you know why?

I'll bite, why?

[rodbolt17]

on most the F motors with electric lift pumps.
at low speed fuel consumption is fairly low.
so Yamaha designed it to cycle the lift pump at speeds below 1200 RPM.
at speeds below 1200 RPM the lift pump would mostly run in a stalled condition heating the fuel and wearing out the pump faster.

so at below 1200 RPM the fuel is constantly being drawn out of the VST but not constantly replaced,cause the lift pump turns off for 20 seconds.

so now we have a small amount of air forming in the lines at the VST inlet.

that relief valve breaks at 10 PSI or so.
when the lift pump turns back on fuel is drawn from the engine filter outlet,through the lift pump and into the VST inlet.
when the VST needle valve closes,VST full, the excess is bled off at 10 psi back to the lift pump intake.

now is where the valve can get ya.

if that valve leaks due to internal corrosion or debris.
what happens now is that small air pocket at the VST inlet starts getting bigger and bigger due to when the lift pump cycles on it will draw fuel out of the relief valve line as well as the fuel filter outlet.
now we have even more air in the lines between the lift pump outlet and the VST inlet.
and it continues to get worse with each cycle until the lift pump is pumping vapors and bubbles.
but remember the VST is constantly having fuel drawn from it but its not getting replaced.
somewhere between 3 to 10 min of speeds below 1200 RPM and the motor shutters some then dies as rail pressure falls.

a quck test, simply use needle nosed pliers and clamp off the line between the valve and the T fitting.
if the low speed stalling quits remove and test the valve.

[Highmark]

So if the valve is bad. it's creating a fuel starvation problem sort a ? or lack of it.
The air bubbles create the starvation right. So that is why after shutting it off and restarting it, It fixes the problem by the pump is now running till I raise the rpm
back up around 1200 or so.. I'm also running 15 1/4 by 19 pitch prop
I was thinking that is was a problem to.
It did not start doing this till last summer. I have been running this prop for 5 years..

[rodbolt17]

I did not say that was the problem.
I explained how the pump cycles on and off below 1200 RPM and what CAN happen if the valve leaks.
its easy to check with needle nose pliers.

[Highmark]

OK No problem.. Just thinking if the valve is bad. that could be what is creation
the condition.

[Highmark]

What is the procedure to test the valve ?
I'm asuming it's a one way 10 psi metered check valve. Correct ?
Push air thru it from each direction ? with meter to validate pressure
opening and closing at correct pressure ?

a quck test, simply use needle nosed pliers and clamp off the line between the valve and the T fitting.
if the low speed stalling quits remove and test the valve.

[rodbolt17]

that procedure will work, requires pulling the air box.
mine doesn't.
its all about not easter egging, peter cottontail at 90/hr aint your buddy and understanding whats missing.

are you missing FUEL
are you missing AIR
are you missing SPARK.
if you have all 3 the dang thing will run.

[Highmark]

Dude. assuming after I do the test you say do by clamping the fuel line
and its does what you say it will due to the valve being dirty or corroded.
What is the test procedure after removing the valve ?
That is what I'm asking.
the engine starts fine it runs fine.
It has spark fuel and air.. It just dies or stalls out at idle...
if I raise the rpm from idle to 9 to 10 rpms and it runs with out dying or stalling

that procedure will work, requires pulling the air box.
mine doesn't.
its all about not easter egging, peter cottontail at 90/hr aint your buddy and understanding whats missing.

are you missing FUEL NO
are you missing AIR NO
are you missing SPARK. NO
if you have all 3 the dang thing will run.