2005 F250 stalling

[Bajabuzz]

New to forum, just found it today.
I have owned my current boat since the begining of this year. It has been trouble free since purchase until today. I have put 200 hours on this engine since March and it now has 1200 hours. It had a full service at time of purchase that included replaceing the dreaded exhaust housing that had some corrosion internally.
We got to the ramp today and launched boat. Engine would turn over and fire right away but stall as soon as key was released. I was able to get engine to run as long as I had engine in nuetral and had throttle opened by pushing button on shifter.
It would continue to stall if I brought throttle back to idle.
Put boat back on trailer and took it home to get ready to drop off to dealer.
Once ready I decided to start it on the trailer just to make sue that it was still malfunctioning. Naturally it started right up and idled so we went back to the ramp and dropped the boat in and started it on the trailer in the water. All worked fine so we launched and drove boat for 15 miles at varying speeds including WOT with no issues.
The 10 mic spin on Racor has not been changed in 200 hours and neither has the filter in the clear plastic can on the engine. Neither show any water in the housings.
I am stumped at this point, looking for feedback

Thank you in advance,

Charlie

[zenoahphobic]

Did you prime the fuel bulb before starting?
Sounds that it was temporarily starved for fuel.
Difficult to see from this end.
And I wonder if you had the chance to turn off the engine (turn key to off)when it did this the first time, and immediately restarted it then, that it would have "reset" itself.

[Nautical]

No expert , but I would check for any ECM codes if you have the diagnostic program. I would be suspicious of the Idle control valve..(may be dirty or sticking).Could be a faulty sensor giving the ECM bad info,or could be some bad fuel.Could try a portable tank with fresh fuel.. Many things to check, but the guys on here will be able to help..

[Bajabuzz]

Thank you for your replies, its great to get feedback so quickly.

Zeno, I did prime bulb after it would not start and stay running. It did not change the symptoms. I have never had to squeez prime bulb on this boat to get it to start. It has always started first time evry time.

The key did get turned off many times during this process since I was tyring to diagnos at dock. Engine cover came off to check fuel level in plastic can (1/2" low). Still did not alter situation.

Nautical, I dont have an ECM reader. Where do I get one? The local Yamaha shops are not well equiped. I do have a short history of auto electrical and auto mechanic in my back ground and this seems like a sensor problem or electrical gremlin since it self repaired.
I use the boat alot and do look at my filters for water or debris but never find any. I had just added fuel to boat the night before. I dont think it is fuel since I was able to run boat for 15 miles with no issues after this problem.

Solo, I will put in new filters since it is due anyways. But nothing is showing in the clear bowl of the Racor. I guess I will just have to wait and see if it repeats the problem.

Thank you again for yor comments.

[99yam40]

a lap top with the Yamaha software , and a hook up cable is needed to connect to your ECU.
Then you need the knowledge to interpret it.
Some have been able to save a screen shot to post so others can help them with the info.
Would be nice to find someone local, but if there is no one, you do what you have to.

The new software is only available to the Yamaha shops, but the older stuff and cable is out there where you should be able to find it.
Just need to make sure what you need on that motor

[Bajabuzz]

Thanks Solo I will try that if problem occours again.

My current plan is to start boat before leaving house either day before or right before departing.

If my problem is similar to your then at least I know it will run after an hour.

We are in peak tuna fishing season in California so dont want it to sit at dealer and not be able to fish. Especially if they then tell me nothing is wrong and I pay a $200 diagnostic bill.

I usually buddy boat and have a towing plan and rarely fish more than 20 miles from shore so I will stick it out and see how it goes.

Thanks again,

[rodbolt17]

are you rigged with command link??

don't worry about any ISC valves, the F250 does not have them.

if working correctly that motor starts at about 2500 RPM and drops.

could have a fuel issue.
could have a CPS issue.

[Bajabuzz]

No command link on this boat. It has mechanical controls.

[sachin2021]

Yamaha in Fiji supplies the F225s with spare water pressure sensors. My F150 did the same and it was a pressure sensor. I stumbled upon it by unplugging various sensors to see if one had gone out. The Yamaha dealership in Fiji ain't of much use.

[99yam40]

No command link on this boat. It has mechanical controls.

Command link and Command link plus are gauges that furnish more info than regular gauges not controls.

Rodbolt is a Yamaha master tech that posts here to help people so hopefully he can give you some good advice if you give the info he asks for

[Bajabuzz]

My mistake on the Command link thing, I assumed that it was the controls. Mine just has the standard gauges. Actually I removed the fuel gauge/speedo panel to install an auto pilot and then added a stand alone fuel gauge elsewhere.
It has been removed for a couple of months now so I cant believe that is part of the problem.

[Bajabuzz]

Rodbolt, when my engine is working correctly it does have a high idle and then comes down, i do not know the exact rpm because i have never looked at intentionally right after startup.
I can check that the next time i start it, but it will be a couple of days before that happens.

What is CPS?

[99yam40]

Crank Position Sensor