Old 03-17-2019, 03:24 PM
Junior Member
Join Date: Mar 2019
Posts: 5
Default 300 hpdi reving up but no going over 28mph

Hello I have a 2004 255 wellcraft fisherman center council, the boat would always run at 50 mph at around 5800-6k rpms... the lower unit recently blew and I had a mechanic replace it.. he also replaces the vst tank, and spark plugs.. engine itself runs perfect and gets on plain fast but once over about 4000 rpms it seems like there is no speed, the boat will max out at about 28mph at about 3900 and will do 6k rpms with no gain in speed, I replaced prop and have and have tried 3 different prop sizes.. I believe the lower unit was a right hand and changed it to left hand rotation, he explained that would not make a difference before any of this the boat sat on trailer and now it is in the water but has only been in the water for about 2 weeks, has bottom paint.please help in any way someone can I'm stuck at a loss here
Taytay367 is offline