power loss

[juanfishon]

Hi ,i recently traded in my 2 x 85hp yamaha's for 2x f70 hp four stroke,my problem is that my boat takes a long time to plain,i have 15 pitch props on the four stroke and had 17 pitch on the two strokes but my pull away is at least half slower,what i also see is that the new four stokes doen't trim down as much as the two stroke used too.could this be my problem?
Also if i get it too plain the revs only goes up too 5300rpm,any help will be appreciated
Thx Juan

[boats.net]

The F70 rpm range is 5300-6300 rpm's, sounds like to drop to a smallet pitch prop.