paolo@unipam.it

Hi everyone, I found this solution: i've changed Stainless steel F5 props, into Aluminium ones, keeping same pitch. Now boats reach 5000 rpm at Wot. Of course I've lost speed (about 2,5 knots at 3500 rpm), but i can increase cruising rpm, and overall engines sound much better and acceleration increased. thanks. Paolo

Hello Everyone. My name is Paolo, from Rome, Italy, and I've bought my first Monterey few days ago. It's a 290scr, year 2007, 2 x 5.0 Volvo GXi/DP- 270hp each, serial n°4012200131 and 4012200128, DPS outdrives with Duoprop stainless F5 props. Less than 100 hours. Now, problem is that engines can't reach max rpms at WOT. Testing several times in sea water, with 5 persons on board, half fuel, full water, no other important weights, clean hull, max rpm was about 4300- 4400 (using trim over neutral position). No more. I thought it was a "too heavy" prop, or something to check in engines. But problem seems different. I contacted a Volvo service point and they checked that gear ratio is 1,95:1. They consider that for this kind of boat right ratio should be 2,31:1 and that is useless to reduce pitch to F4 or F3. They said that changing props and reducing pitch, even if I could reach max 5000 RPMs, the speed would be significantly reduced, considering that a lower pitch prop with higher speed rotation can have a lower efficiency. Change ratio gear is an important cost, in Italy around 9000$, so before taking a decision I would find more information. So I ask to Most and all users if other 290's with same engines had similar problem, or which kind of props and gear ratio they have. thanks Paolo