Re: does tis seem right 90 johnson
In order to see how you are doing, try to calculate the speed formula, earlier posted by JB. Usually quite accurate. If your boat isnt too heavy your should be turning at least a 19" on that boat. Formula is:<br /><br /> posted June 21, 2002 09:50 AM <br />________________________________________<br />There is another formula for predicting top speed if ideally propped and trimmed.<br /><br />Prop HP=A<br />Boat gross wght.=B<br />Bottom factor=C: 180 for V bottom, 200 for nearly flat, 225 for Flat.<br /><br />Take the square root of A/B and multiply by C.<br /><br />Example: My Montauk has 70hp, weighs about 1900lb. with max load. 70/1900 =.037. Sq. rt of .037 =.19,<br />Nearly flat bottom factor, 200 X .19 = 38.4mph.<br /><br />GPS WOT reads 38.5mph <br /><br />--------------------<br />Red sky at night. . .<br /><br />Are you sure your tank and fuel connections are good to supply the fuel the V4 needs ? Tank vented, lines tight ? How deep is the motors antiventilation plate compared to lowest point of keel. At 5600 RPM with a 17" pitch your theoretically speed is 45.5 MPH which leads to a slip percentage of around 10%, not uncommon. Sound like the motor isnt performing its best.Do the speed calculaon and compare.