My 1993 Yamaha 25hp 2 stroke displayed some strange behavior this past weekend. After idling through a shallow weedy bay, it would not come up to speed. The engine sounded like it was revving up, but the power seemingly was not getting to the prop. I checked the prop and lower unit for weeds, but it was clean. By stopping, and putting it into reverse for a moment, and then going back into forward, it did go back up to speed. When the boat is running normally, the motor is runs smooth, as it does at idle. <br /><br />This behavior is new, and (coincidentally) happened with 2 other people in the boat with me. My suspicion is that I did not re-install the linkage correctly when replacing the water pump back this spring. I have also noticed that in reverse, the motor will occasionally slip out of gear. Does this make sense, and if so, any guidance on how to fine tune it? The manual gives information on how to remove and lower the lower unit, but I neglected to count the number of turns on the nut correctly. <br /> <br />Second question that may be related: The boat the motor is mounted on is a 16.5 foot aluminum sea nymph. I can get 23 mph via my GPS, but the throttle is only at about the halfway mark. Further advancement of the throttle does not result in additional speed or a change in the motors pitch. It does not have a tachometer, so I dont know what my RPMs are. I am planning to attach a Tiny Tach to the motor to give me a better understanding of it. Is this condition normal, or does it indicate something is amiss. <br /><br />Thanks<br />nodima
