BruceK
Well-Known Member
The Sc, s on the KAD 300 powered boat I had cut in @1400 and disengaged @ 2400 , with the caveat the turbos were in fine fettle .
It could stay ar say 2900 or 3000 rpm all day , waves just made the speedo vary .
However if the turbos start to fail then boost is lost so intermittently at say 3100 rpm one of the SC,s would kick in , and start hunting and there would be a significant reduction of speed until the correct boost re established.
My engineer diagnosed worn turbos and suggested refurbing them ,
I sold the boat and the buyers surveyor picked up on this so I knocked a bit off of a pre elivated price .
So this kicking in of the SC ,s way above the 2400 rpm cut out could be worn turbo related .
I suppose there’s some sort of boost pressure test - one for Volvo Paul ?
That is a very real possibility. I had a look at the turbos last year. Visually the blades looked fine. Not the best of tests. I will send them in to a specialist to refurb. It doesnt solve that screech though.