225 efi lost top end rpms

[SilverFox579]

If you don't have access to a DSO (or Diagnostic System)- another option that's better than a DVOM would be an ANALOG voltmeter (ie: Needle-display device). Not too hard to see the twitches and jumps of the needle.

There are some things an analog meter still excels at.

[Bob G.]

I have a Simpson 260 analog meter from the early 80’s. I looked at their website and they still make them.

[SilverFox579]

Same one I have Bob, also from early 80s!

[Ryno 615]

PROBLEM SOLVED! I wanted to post an update to this as several people have messaged me regarding this issue over a period of time. I decided to run the boat hard for a few miles, pul the cowling, then shoot the temp of each coil with an infrared thermometer. Cylinders 1-5 ranged from 104-108 degrees, number 6 was showing 94 degrees. Wasn't sure if that would matter, but was worth replacing. I tried to order a new coil from Don, and they are discontinued. He recommended trying CDI Electronics, and they were able to get a coil. I pulled the coil wire off my old coil and inspected it, and noticed that there was hardly any wire touching the coil. So I trimmed maybe 1/2" until I found "good wire". All 6 coils looked identical, so I trimmed every one of them. May have not contributed to the fix, but I felt better after trimming them. My thoughts were that maybe the #6 coil was not firing correctly at higher rpms, and I did not have a way to test that. Anyways, I ran it today and have my rpm's back to normal. Hope someone can find this info useful. Big thanks to everyone on this thread, I really appreciate it.

[EuropeanAM]