Misfire , engine stalled now i have a crank no start

[snakebitmark]

While i was idleing my 2004 225 opti SERIAL NUMBER 0T907156 i developed a chugging misfire, at first i thought i was fouling a plug i got the boat on plane for a bout 300 yards without a problem brought it back down to an idle and the misfire was no better maybe even worse. But now the idle was increasing on its own up to about 2500 rpm NO ALARMS , i got her back to the ramp tried to get it on the trailer now i have crank no start condition. I get the boat back in the barn pull the plugs and find no damage no shredded belts all the plugs look just o.k. cylinders 3 and 5 look a little fouled but not horrible. Compression on all the cylinders were 103 to 111 psi. I have had plugs go bad before this just didn't feel like a spark plug issue, anyone have any idea what would cause this to happen. I will be replacing the plugs today and continuing to trouble shoot , your input is appreciated. Someone suggested it could be a tacker diaphram, what is that ?

[JOE54]

diaphragm in fuel rail needed for precise injection operation on an opti , located in stbd fuel rail ,known problem with optis, good luck someone

[snakebitmark]

diaphragm in fuel rail needed for precise injection operation on an opti , located in stbd fuel rail ,known problem with optis, good luck someone

I did look this up, but it seems that most complaints were a poor idle , but nothing about high idle at closed throttle

[lpugh]

I did look this up, but it seems that most complaints were a poor idle , but nothing about high idle at closed throttle

Common complaint as well

[snakebitmark]

Common complaint as well

Really, i will do some more reasearch. I resolved the no start issue, when i ran the new transducer cables and removed the old ones i must have hit the switch in the channel, the problem finally showed up. I have spark and fuel just need to wait for the auto parts store to deliver the new spark plugs.

Thanks Leon and Joe.

[SilverFox579]

But now the idle was increasing on its own up to about 2500 rpm NO ALARMS

Classic indication of tracker valve failure just like Joe54 said, who btw, happens to be a highly regarded certified Mercury technician and is the "someone" who recommended it to you in the Mercury forum.

[Savage]

Classic indication of tracker valve failure just like Joe54 said, who btw, happens to be a highly regarded certified Mercury technician and is the "someone" who recommended it to you in the Mercury forum.

Agree......100%!!!!!

[EuropeanAM]

The high RPM's with no throttle input indicate that UN-METERED FUEL is getting into the engine.

IE: Coming from somewhere other than the intended path (through the injectors as demanded by the PCM).

Check the Air/Fuel Pressures with a DUAL PRESSURE, glycerin-dampened gauge set. Record results:

-At idle
-Under Acceleration
-5/10/15 seconds after shutdown (restart for each time period)

Results can assist in knowing areas to look at (such as tracker valve, FP Regulator, Compressor, Air Leaks, etc).

[snakebitmark]

Agree......100%!!!!!

I removed the tracker valve , and found multiple cracks on the fuel rail side of the valve and one nice pin hole or tear about 1/16 to 1/8 of an inch going through the other side. I will post some pictures later. Now i need to wait till Monday and try to get it at a local supplier. I will post again when i finish the repair.

[snakebitmark]

20200516_165104.jpg20200516_165031.jpg

Agree......100%!!!!!

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I removed the tracker valve , and found multiple cracks on the fuel rail side of the valve and one nice pin hole or tear about 1/16 to 1/8 of an inch going through the other side. I will post some pictures later. Now i need to wait till Monday and try to get it at a local supplier. I will post again when i finish the repair.

[snakebitmark]

Classic indication of tracker valve failure just like Joe54 said, who btw, happens to be a highly regarded certified Mercury technician and is the "someone" who recommended it to you in the Mercury forum.

I'm grateful for all the help, good people on here.

[SilverFox579]

Yep, lots of good people here and I've learned a lot from several Don, Savage, Joe54, just to mention a few.

[snakebitmark]

UDATE... I replaced the tracker valve, and the engine runs great. She fired up on the hose with just a touch of the key. So a big thank you to all involed. Hope this will help others in the future that find themselves with similiar problems.