Evinrude 90hp help

[Wormdrowner]

Purchased a 16' Sylvan with a 1992 Evinrude 90hp. Since buying the boat I have an intermittant problem with it losing power. Sometimes it runs fantastic, 40mph and 4800rpm, when it loses power it runs around 2200rpm. It idles and troll fine. I know this sounds strange, but when I go over another boats wake that will sometimes trigger the problem. Changed plugs and wires, ran great for two trips and now it's doing the same thing again. What I've done so far is: plus and wires, drained built in gas tank, changed fuel filter, carbs rebuilt, used different gas tank and hose thinking there might be something in the tank. Compression is 125lbs in all four cylinders. last night tried tapping on the CDI box to see if that did anything, it didn't. Would a CDI box cause this problem? I hate to keep throwing money at things when I don't know what causing this. Any help would be greatly appreciated.

[Eric Wettschreck]

It's interesting that you say it happens mostly when you hit a wake. That would tell me that something may be loose....maybe. Or, a carb float could be sticking. Just thinking out loud here. Have you checked all your electrical connections to make sure they are not corroded and snug?

[Wormdrowner]

Checked all electrical connections, rebuilt carbs although they looked extremely clean. Took it to a certified marine mechanic that lives near a lake, went over our own wake numerous times but of course it wouldn't happen with him in the boat.

[marine_man]

When it drops off, is it for an extended period? I'd be tempted to take a timing light with and when it does it, see what the ignition system is doing.

marine_man