Mercury Optimax Shuts down over 5000rpm

[ExtremeTards]

I have twin Optimax 225hp 3.0L outboards behind a 29ft gofast. The starboard engine only, when running below 5000rpms it runs all day, if I push beyond that 5000rpm, it runs for a couple minutes then just shuts off, no stutter, no hesitation. It will start back up immediately if I turn the key switch off and on. It's not a fuel problem because I've checked to make sure the lines are still primed and there is fuel pressure in the rails. Anyone have any other ideas? I'm wondering if a faulty TPS can cause this, because the TPS needs changing as it gives trouble, eg. if I rev on land and bring the throttle back to idle, it doesn't come all the way back down and idles 500rpm higher until I use my finger to touch it back in place and bring the idle back down to normal.

[rocketman6965]

Optimax should not be revved in idle. It will cause a fault code and “learn” a new idle position. Throttle cable must always go back to stop on block. Perfect adjustment is enough to hold a piece of paper but not tear it when you pull it out.

[ExtremeTards]

Appreciate the advice, but that doesn't address the real issue that I'm having. I'm more concerned as to why the engine would just cut off after running it over 5000rpm for a couple minutes (between 5-10minutes of run time).

Optimax should not be revved in idle. It will cause a fault code and “learn” a new idle position. Throttle cable must always go back to stop on block. Perfect adjustment is enough to hold a piece of paper but not tear it when you pull it out.

[Motv18]

Check the buzzers working, don’t know any code that would kill it though, sept a faulty kill switch.

If the tps zeros out it can kill it. You can also check the lower unit for a bind.

Normally your out looking at reduced power, or limp mode just straight up dieing will take some looking into.

when you say touch the butterfly or throttle lever on the motor. Stuck butterfly is a problem.

[ExtremeTards]

Yeah the buzzers are fine and the kill switches are working. Both engines would cut off with the faulty kill switch.
I'm going to swap out the TPS and see if the problem transfers to the other engine. Seems like a good place to start.

Touch the throttle lever on the powerhead. The butterflies are fine. The TPS arm itself is what seems to be sticking. After you unclip the throttle cable and use the connector rods to increase rpm, when you let it go, i t doesn't always go back to original position and remains with a slightly higher rev.

Someone also said a faulty Crank Position Sensor may cause that cut off. It's just really weird that it only happens after cruising passed 5000rmp only. Usually a fault would send it into guardian mode and reduce you to 3000rpm, but this one has me baffled.

Check the buzzers working, don’t know any code that would kill it though, sept a faulty kill switch.

If the tps zeros out it can kill it. You can also check the lower unit for a bind.

Normally your out looking at reduced power, or limp mode just straight up dieing will take some looking into.

when you say touch the butterfly or throttle lever on the motor. Stuck butterfly is a problem.

[XstreamVking]

I use pure silicone spray on my tps's. Helps to keep things moving freely without grease gumming it up. There is also a roller on the throttle linkage that can flat spot and cause problems too. Look it over well. These opti's are very contrary motors when they have a problem.

[Motv18]

You know I want to say lose ground as for it dieing. Snug but the vibrations at 5k break it.

With the remote unsynched, the shift might be as well, not sure an opti would but that would be more like a miss soooo probably not the shift switch.

If if you have a primer bulb is it in backwards, nah that would affect other rpm

alternator humm that would cause problems at all rpm, well cemf issues with the exciter might shut it down, but I think you would see issues as it approached 5k. Humm

gonna have to go with first though has to be some electrical break happening.