I met with the mechanics today and spoke to them for a while. First of all they told me the first things that they did was clean the fuel pickup and anti siphon valve (they did clear some gonk out of it) but it didn’t fix issue.

They did hook up a fuel pressure gauge and do a measurement when the issue manifested and found there was no fuel pressure change. They also said the computer recording did not throw any code and everything looked normal thats why they were having difficulty identifying. They said when they’re running it at 4000 RPM the issue did not occur (it’s only occurring at about 3000 to 3500 RPM which is the sweet spot for the boat). They did suggest (before I did) hooking up a fuel tank and they also have what they call a boat-in-a-box which lets them hookup to the boats wiring to see if there’s an electrical issue. They also mentioned the possibility of a TPS (throttle position sensor) issue, but that costs $1,400 to replace so they are going to test with portable tank and boat-in-a-box first.

I assume replacing the ECM would be costly too (if the part is even available). One thing I never thought to try was to turn engine off for a minute when it does occur. If it is related to the computer but its fixing itself every time I take the boat out perhaps powering it down and letting electricity dissipate out of it would help.

Thank you,

Scott

To clarify I found the TPS on Amazon for $45 and they told me that’s not the part and that for mine it is part of the throttle assembly unfortunately. Its part 802622a1

They said it’s no longer available from Mercury, but that I may find it used or after market and they told me when Mercury did have it available they charged $1,400 for it. For that reason they suggested that we try hooking up fuel tank and boat-in-a-box first.