engine rattle @ 2200 rpm, then disappears?

chopperdog

Seaman
Joined
Jun 7, 2009
Messages
71
1988 OMC 3.0l, 4 cyl with OMC Cobra outdrive.
Newly rebuilt outdrive, New valve job, runs great (seems to).

The engine makes this weird rattle, almost like a buzz, at 2200 rpm, then goes away at like 2300. It then reappears at around 3200 rpm, and goes away at like 3300.

It sounds like a metal pie pan type of noise.

This rattle is both when in or out of gear. I think it is coming from the engine, not the outdrive.
It almost sounds like the carb, but I can't tell.
It is not the flame arrestor, I removed that, and there was still a rattle.

Could it be a harmonic buzz of a component, or is it more serious?

Thanks.
 
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