Stalling Yamaha F150

[boatmangc]

Send the injectors to Flagship, you'll need them.

[high sierra]

Yamaha OK

I took the 18 outrage to the lake yesterday and the Yamaha motor ran EXCELLENT. No stumble , no coughing and the power is back. In fact the RPM with the Solas prop has picked up 200 rpm. I ran the boat wide open for 7 miles coming back and it was a pleasure to drive, 41 mph at 6000 revs. It was quieter with the new balance shafts and the new computer allowed slightly higher revs.
This has been a long struggle to get this fixed and the dealer although not trained on this motor , tried very hard to correct the problem's'. The breakdown was the tec who with an arrogant attitude and not enough training took too long to find the problem. He did finally apparantly find the solution after changing every sensor and the computer.
A conclusive cure I'm not sure , but a pressure sensor along with the computer module were the last things changed.
Thanks to all for the input and interest. Gone fishing! high sierra

[99yam40]

what pressure sensor was it that they replaced

and how many times did they replace the computer module

[high sierra]

Yamaha now not stalling

99yam40, the pressure sensor was part # 63p82380-00 . They replaced the computer 3 times and I ended up with a zero time new one that the tec put on in a last ditch effort. The motor ran better than when new. Very smooth and powerful. I'm elated. It is a good motor after all. Thanks, high sierra

[Sparkieboat]

congrats..I am glad to hear everything went well. did you say you had it on a 18' outrage? 41MPH at 6000 RPMs?? I have my 115 on a 19' sea pro and i was hitting about the same speed and RPMs. I am sure my boat will easily do 50 MPH with a 150. my boat is the bay design, maybe that makes a difference.
still waiting to hear back from the shop that has my boat.
Also was the computer showing a fault with the pressure sensor?

[high sierra]

Yamaha

Sparkieboat , The boat will do 50 at sea level. I am running a 15 by 15 Solas at 5 to 7 thousand feet . Sea level requires a 19 inch pitch. I use a modified Turbo stainless at sea level.
Don't know on the final diagnostic. The tec wouldn't talk to me. He fled the scene. Ha , high sierra

[Sparkieboat]

roger, I did not think about the elevation effect. I would run to...LOL

[99yam40]

99yam40, the pressure sensor was part # 63p82380-00 . They replaced the computer 3 times and I ended up with a zero time new one that the tec put on in a last ditch efort. The motor ran better than when new. Very smooth and powerful. I'm elated. It is a good motor after all. Thanks, high sierra

I guess that was the sensor Rodbolt called the MAP that takes the barometric pressure at key on, as it is one the manifold.
Did they replace that more than once, or just at the last?

If they tried 3 different ECUs and only one replacement MAP, then I would say that was the problem all along, nothing to do with the so called mystery of an injector shorting out dragging down the 5v reference.

[rodbolt17]

that is indeed the MAP sensor.
at key on it takes a barometric pressure reading and locks it in for the rest of the key cycle.
once the engine is running it then measures intake manifold absolute pressure.
if the sensor is bad OR loading down the 5V reference then the output of THAT sensor and most the rest using that 5V reference, will be INCORRECT.
but the stupid ECU does not monitor the 5V reference and you CAN get an in range failure that sets no codes.
had one last summer that the map sensor told the ECU that baro pressure was 19"Hg.
the ECU complied with the input.
at se*****l it did not work.
5V ref circuit had failed partially.
its an incredibly simple system.
like I said, couple weeks back I got in an F225, same basic system.
two other dealers gave up on the off idle stumble/stall issue.

took less than 20 mins to diagnose,fix and verify the fix.

the TPS ref voltage was low causing the TPS output voltage to be low BUT still in range so no codes.
unplugged the TPS and 5V ref returned, plugged it in and it dropped to 4.2 with an output of .66V, range is .7 plus or minus .05.
however as the TPS output tried to increase the ref voltage got loaded futher thereby increasing the loss of feed back voltage but it stayed in range.

trusty eyes and my DMM had it solved.

that stupid ECU simply reacted to the information it got fed.

oh and the ECU change has nothing to do with your engine running different.

[high sierra]

Yamaha

Hi all, well this has been a long strange story on my Yamaha 150 four stroke. As I reported a couple of days ago the motor ran great , never missing a beat.(and it is faster by 200 rpm) Well today when I was out ( my wife took the call) the Tec called and wanted to know how the motor was running and if I was pleased with the repair. He was very pleasant and cordial talking to my wife. He did seem concerned. Perhaps the stress was getting to him as well and not only me and the shop manager.
I was amazed and pleased that he called. This type of communication speaks well for Yamaha and maybe even superman listens when someone tugs on his cape. I am very satisfied with the outcome . high sierra

[99yam40]

Good to hear it is still going great, your map must have been going bad for a while or from the beginning and now with the new one you gained 200 RPM.

I thought they had replaced all sensors early on, but I must have been mistaken on what I read.

[Sparkieboat]

I would like to yank on super mans cape...lol
Glad to hear he did a follow up call..it show some pride in his work. I am sure he was pushed to his limits while trying to fix the motor. I would imagine your motor is now responsible for at least 5 new profane words the world has never heard before...LOL

My super man got his cape stuck in the phone booth and is still trying to fly over to my motor and fix it, but you know them capes, they get stuck on everything.

[high sierra]

Yamaha

99yam40, they did say they had changed all the sensors. You are not mistaken. I only went by what they said. I do believe they kept changing parts as the problem was intermittent. It seemed to crap out when I drove in 20 to 30 degree weather. The dealer wouldn't go out in that weather. I'm just glad it runs very well now. Gone fishing. high sierra

[Tucker]

Sorry, just gotta ask, where'd the 200 RPM's come from? I thought all this new stuff was digidal and dead nuts on? Isn't there some gizmo on there counting RPM's and maintaining a spec.

[high sierra]

Yamaha

Tucker, I'm not sure. Perhaps the readjustment of the throttle plates. Maybe I've lost weight worrying. Going to go out this week again fishing. We'll see. high sierra