1988 OMC 5.0
502APRGDP
Engine just started making a loud knocking today while running on water muffs at low idle. Was idling fine and then knocking sound just started. Knocking increases when RPMs increase. I pulled the valve cover on starboard side and checked the push rods. All look ok. Haven't checked under valve cover on port side. Ran out of daylight.
I have videos with sound it started making today and how it sounded just 2 weeks ago, when it was running great.
What changed in 2 weeks? I just rebuilt and reinstalled carb. I also was rotating the engine by hand (to check the lifting and falling of intake and exhaust valves).
I'm not sure where to focus. Could it be rod knock or spun rod bearing and if so could it just start that quickly? Timing off from manually rotating engine? Bad lifter(s)?
No knocking when engine turns over with starter. Knocking begins once combustion in engine begins.
502APRGDP
Engine just started making a loud knocking today while running on water muffs at low idle. Was idling fine and then knocking sound just started. Knocking increases when RPMs increase. I pulled the valve cover on starboard side and checked the push rods. All look ok. Haven't checked under valve cover on port side. Ran out of daylight.
I have videos with sound it started making today and how it sounded just 2 weeks ago, when it was running great.
What changed in 2 weeks? I just rebuilt and reinstalled carb. I also was rotating the engine by hand (to check the lifting and falling of intake and exhaust valves).
I'm not sure where to focus. Could it be rod knock or spun rod bearing and if so could it just start that quickly? Timing off from manually rotating engine? Bad lifter(s)?
No knocking when engine turns over with starter. Knocking begins once combustion in engine begins.
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