down on speed

[inmotion]

Hi all i have a 1999 Carver 530 with a pair of Cummins 6CTA 450HP engines and i am way down on speed. WOT is 2240RPMs and only delivers 16 knots … i have previously had it up to 22 knots… bottom of the boat is clean both engines have been rebuilt by Cummins… air filters all new… i am stumped on this tried trim tabs in all different positions with minimal affect… is there something i am missing..

Topic

[Tony Athens]

Like Clark said, close to zero infor to work with.. Have you gone thru this article and not skipped anything ?–That would be the basic way to start.

https://www.sbmar.com/featured-article/understanding-low-power-troubleshooting/        

[Clark Leighs]

Need more info to even start.

–Do you have EGT guages, both engines?

–boost guages as above?

–Double checked the tachs at the engines with a handheld tach  from Ebay?   about $20-$30.

__Do you have boost gauges?  both engines? readings?

–any engine smoking, either engine?  Appearance, colour and odour?

 

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[Author]

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