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Recent content by Brian O.

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    1991 OMC 5.7 Cobra - WOT top end surge/bog

    Louc/Mark, Thank for your input. Here are my answers: "How about the opening of your secondaries? Vacuum operated I'd assume. If they open too soon, you could have that same effect. Also is this carb original to the engine? 750 CFM seems big for a 5.7, has it always had this problem? I'd...
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    1991 OMC 5.7 Cobra - WOT top end surge/bog

    Greetings, I wanted to update those who might have been following this as to the latest on my quest to solve this issue. Since originally posting I've: 1. Replaced the anti-siphon valve. 2. Cleared out the tank vent (it was partially clogged but not completely) Based on some observations I...
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    1991 OMC 5.7 Cobra - WOT top end surge/bog

    AllDodge, Thank you for the input. Your response triggered some thoughts based on work I'd done that I didn't mention: 1. I checked the pickup tube going into the tank. It was clear. That was one of the first things I looked at. 2. I did pull the anti-siphon valve off. You could readily see...
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    1991 OMC 5.7 Cobra - WOT top end surge/bog

    Greetings all, First time poster here looking for some direction on my recently acquired 23’ Chris craft cruiser. It has a 5.7 OMC I/O setup and runs very well for its age overall. Very happy with it. My one gripe is that at full throttle, on plane and cruising in calm lake water I notice a...
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