QSB 5.9 230 hp not getting max rpm

[Dennis Asbury]

I have a 2009 QSB5.9 230 hp with ~2500 hours. It is in a trawler (single), and I typically run it between 1650 and 1800 rpm. Aftercooler serviced 1 year ago per sbmar recommendations – fully tested. <br />yesterday I tried to run it up to max rpm and it wouldn’t go past 2000 rpm with minor black smoke. Engine temp was stable. <br />I have a new environment air breather kit on it. <br />engine runs great but won’t spin above 2000 – where should I start looking?<br /><br />

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[Dennis Asbury]

Thanks for the reply. Because of where I live  – gulf coast of Florida, my hull and running gear is cleaned every 4 weeks and I get a report. I just had it done 2 weeks ago and I’m confident it is clean 

[Fireisland1]

The very first thing I would do is send in a diver. Check the hull , prop and rudder. That must be eliminated as a culprit .  

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Tony Athens

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