I have a 2003 two stroke Yamaha 115. I am running this on a 17 foot Action Craft (910 lbs)and am having trouble getting the speed much over 43-44 mph. Before you jump on the prop, I have run Trophys and Lasers in different pitches from 19 through 22 and the speed changes only minimally (1 mph or so) with all of these props. Before you start talking about trim and motor heigth, let it be known I have been running boats for quite a while and tend to milk more speed out of boats than most. The boat originally came with a 90 Merc and I was able to get it up to 42 with it. The motor runs strong up to @5300 rpms unless I take it too high with the jackplate then I can get it up to 5600 but then I start blowing out and the speed drops. <br /><br />Given that, is expecting 48-49 mph too optimistic with this set up. If so, are there any performance changes I can do to the motor to milk some more speed out of it, more to the point, what are the differences between the 115 and 130. They look like twins but I have a friend with a 130 on a 17 foot Master Angler that I can get 50 mph out of. The two motors look like twins with the cowling off. From what I can tell the powerhead and lower unit are the same. Any help.<br /><br />I know it would be cheaper to trade up to the 130 than to modify but that motor is no longer made and if I traded up, I would probably go all the way to the 150, but I worry about the added weight in the back and I would have to upgrade to a 6" jackplate, plus I just had a Bob's lower unit put on it so that the motor could get water at the high motor settings so I am not keen on trading the motor in. <br /><br />Bottom line, any way to see if I am getting 115 hp out of the motor and is there anyway to get 130 or more out of it.
