WOT RPM Too Low - major issue? cause?

[artg]

Rev up...cut out....in neutral could be ecm controlled. This would make since to protect the engine.

If everything is running good and no sputters or misses, check your throttle cable. You could have extra slack in the cable.

HMB - thanks for your inputs!

I'm currently far away from the boat, but before I left I was able to try WOT a few more times in different conditions, and took a peek at the spark plug wires.

I noticed upon closer inspection that the Perfect Pass RPMs (digital) were 100-200 less than analog tach depending on the day/speed (see pics), and when I was alone in the boat the last time I was able to get it up to 4600 (digital)/4800 (analog) and 40.4 MPH. Also just realized that the Speeds aren't matching - GPS PP is 40.4 when boat says 42. Both tachs run off the same signal, so not sure why they'd be that far off or which to trust as more definitive...? My wakeplate was all the way down (nose down), not sure if that should have been be as high up as possible to minimize load?... After researching I've seen at least one account (at lower speeds in the 30's) where wakeplate all the way down vs. up was a 2-2.5mph difference. Assuming that's mph and a corresponding RPM difference, seems possible I get a healthy RPM and speed at WOT after raising wakeplate... I normally have wakeplate down so I didn't think about it at first...

The spark wires I looked at were corroded (see pic) and flame arrestor had gunk and needs to be cleaned. So I'm planning to start with the easy stuff (hopefully easy) as part of my winterization this year -> replace Spark Plugs, Spark Plug wires, Distributor Cap and Rotor, Fuel Filter (there's just one not two right?), PCV Valve along with Oil Filter, Engine Oil, V Drive Fluid, Transmission Fluid as part of winterization. I'm planning to do those as the last thing before I pull her out of the water so I can hopefully take it for a spin afterwards and see if anything got better

If I have the time and energy I'll try to test fuel pressure and compression test the engine as well.

I'm amassing all the parts/materials and will plan to report back in a few weeks after I've had a chance to work on it.

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