250 Pro XS Power Loss

[PickettZ9]

Serial # 2B113631
2015 ProXs on Nitro Z9
25 Tempest Plus
58-5900 RPM WOT/19-20 PSI H20
Merc Monitor (from Don)


Running into weigh in, 5800 rpms, water pressure at 20, 123 degrees on temp, strong outlet stream. it started to lose power. Dropped down to 4200 rpms, then 3200. No warning beeps but my Merc Monitor flashed alarm. I know my alarm tone works because it beeps every time I start the motor. I always make sure of this. The alarm stated, ⚠️ Warning, Starboard System Sensor Loss. Reduce RPMs and Guardian Mode Activated. When I’ve had alarms before, it would give me a code. Not this time. New water pump and impeller earlier this year. Plugs and wires are over a year old though. New reserve tank last year due to stripped cap and dropped magnet. New oil pump at same time due to leak. I use the Quik Kleen and Care together every fill up. I clean the compressor water filter beginning every year as well due to the junk in our southern lakes. Sometimes monthly when the sylvania starts getting thick. So I decided since it said system sensor, let me just check the stats. Starboard was clean, opened and closed at 130 degree water on stove. Port stat had a stick lodged in between not allowing it to fully close. But did function with the 130 degree water. So my question is, could the port stat affect the starboard stat pressure wise??? Again, I really don’t know where to start as the alarm gave me no code like normally, just saying system sensor failure. And it didn’t overheat per my Merc Monitor. Has anyone seen this alarm before with no audibles or codes to go by? I’m open to any suggestions or guidance. Thanks kindly.

[lpugh]

compression test first thing

[JOE54]

yup

[PickettZ9]

compression test first thing

Ok. I always check compression when I do plug and wire changes, which will be happening this week.

[PickettZ9]

yup

I thought they may work in conjunction with each other. It’s just always given me a code on that Merc Monitor and/or alarm tone. I’ve got stats and gaskets coming. These southern lakes wreak havoc on our cooling components. Being Longview I see you probably know!

[JOE54]

every day man every day

[EuropeanAM]

I thought they may work in conjunction with each other. It’s just always given me a code on that Merc Monitor and/or alarm tone. I’ve got stats and gaskets coming. These southern lakes wreak havoc on our cooling components. Being Longview I see you probably know!

To answer your question, a Port Stat held open can indeed cause an overheat on the STB bank of cylinders (primarily at or just off idle).

In addition to checking the basics, you really need a Full Report on this from a suitable diagnostic system (G3-2024, Diacom, etc).

[PickettZ9]

To answer your question, a Port Stat held open can indeed cause an overheat on the STB bank of cylinders (primarily at or just off idle).

In addition to checking the basics, you really need a Full Report on this from a suitable diagnostic system (G3-2024, Diacom, etc).

Yes sir. Thanks Don. I have already contacted a local authorized dealer for scan. Most are closed Monday locally here. I also have a diagnostic disc and cable coming for my laptop. Will be reporting back by end of week hopefully as to not leave a thread with a problem “unanswered”. Thanks again!

[lpugh]

In this order:
Test the battery (950 cca minimum 185 minutes reserve capacity
on the muffs
Monitor Air/ pressures while warming up motor
watch the temps on the scan tool, both sides should come up to about 130 degrees in less than 5 minutes, you will notice a drop when they open
shut off motor and watch the leak down rates for 30 seconds take note of all this data
print the fault history stored in the computer
pull the spark plugs, pull the kill switch cord
Prop throttle wide open
connect a battery charger
preform compression test and evaluate plug condition

Post all results here
now you will have enough info to establish a plan of attack, more tests may be required based on results so far

[PickettZ9]

In this order:
Test the battery (950 cca minimum 185 minutes reserve capacity
on the muffs
Monitor Air/ pressures while warming up motor
watch the temps on the scan tool, both sides should come up to about 130 degrees in less than 5 minutes, you will notice a drop when they open
shut off motor and watch the leak down rates for 30 seconds take note of all this data
print the fault history stored in the computer
pull the spark plugs, pull the kill switch cord
Prop throttle wide open
connect a battery charger
preform compression test and evaluate plug condition

Post all results here

now you will have enough info to establish a plan of attack, more tests may be required based on results so far

All above tests were perfect and in specs!!
We did scan and find the problem…….Water Pressure Sensor!!!! Same exact thing on my previous Opti. Replaced and she’s back to screaming like scolded dog!!!
Thanks for all your input and help!!

[EuropeanAM]

Was it an open or short?

[PickettZ9]

Don,
I honestly don’t know. 26 years of being electrician and now in office, I just had a hunch when it said sensor system failure, look at sensors. I have the old one though and can see if it doesn’t have to be in the system. Surprised at how much works on closed loop and alarms on opens. (Much more used to opposite)
Anyways, I checked stats first and found little debris in stats. Water intake screen had little trash. So I went ahead and cleaned screen obviously and changed stats and gaskets, even though they did work properly. I then went ahead and checked Poppet Valve and it was very clean as well. My battery is Optima, 1100 MCA. Load tested, all was good. I moved to plugs and wires next. They were over 365 days old. They looked ok, but needed changing and correct gapping regardless. Again, looking at things in a troubleshooting manner, I asked myself water pressure read good on Merc Monitor, but what if it didn’t on a sensor? I remembered on my old Opti having same problem one time. I didn’t have a Merc Monitor, but remembered getting an alarm but pressure was reading good and it was the sensor. So I asked my authorized tech to be sure and let’s check that. What are the odds?…..well twice now. I always order 2 of things with parts and had one in my shop so no lead time. (Ha!) I was able to run Friday and it run great. 6900 RPMs, 25-26 PSI WOT, 2-4 IDLE PSI, and no alarms! (And also run great Saturday on a 5 mile run as I won 1st and BB ��)
Thanks as always for the correct guidance and inputs.

[EuropeanAM]

All sounds great except for the 6900 RPM's. Can you say "DUCK"?

Just kidding, obviously meant that to be 5900.