700hp scarab
 

Why cant i get my 1996 26' Scarab to go over 70mph? It went 70mph with a 500hp motor and now it has a 700hp 540ci and it still wont break 70? I have tryed a 25 p, 26.5p, 28p, and a 30p prop nothing will bring the boat over 70mph. Could it be the outdrive ratio keeping the boat restricted. If this boat wont break 70mph it will be for sale! Please help!!!

Is it getting enough fuel, did you use stock fuel pump,carb or is injected

Has motor been dyno'ed is it really 700. Reason i ask is might boats engine was built to 600 by previous owner and its not even close more like 450-500

fuel system
 

it has a areo A1000 electric fuel pump 1/2 fuel line a quick fuel 1050cfm carb and the fuel pressure is 7-8 at idle im wairing on a sending unit so i can hook up my fuel pressure gauge on the dash.

Are you using GPS speeds? Just trying to think that maybe your speedo is off and you really have gained some speed. I would think you would get mid 80s with that HP unless your prop is slipping or some other drive related issue not putting all the power to the water.

fuel system
 

it has a areo A1000 electric fuel pump 1/2 fuel line a quick fuel 1050cfm carb and the fuel pressure is 7-8 at idle im wairing on a sending unit so i can hook up my fuel pressure gauge on the dash.

dyno result
 

yes the motor has been on the dyno i was there to witness it it made 698hp at 5800rpm and also i have a gps speedo and i checked that with a hand held gps

what RPM are you turning in the boat now ? hull could be wet and way heavy or a bad hook from bad trailer set up...

its turning 4900rpm

Are you hitting the rev limiter,on a stock merk rev is 4850, if it is fire power it is 5350