没有转速表。我上网问了一下，这是一个比较明白船的人的回答。

Engine revs up but the boat slows (or doesn't speed up) can be caused by three things (I'm betting on #1 or #2):

1. Ventilation: air gets sucked into the blades, either surface air cause the prop is too shallow or damage to the antiventilation plate, or exhaust gases being drawn into the blades usually because of damage to the diffuser ring on the prop, or a foreign object caught in the diffuser ring. The prop is pushing air instead of water, reduces the load on the engine and lets it rev up without pushing the boat. A couple tiny pieces of gravel is all it takes.

2. Cavitation: if the smooth flow of water into the blades gets blocked by underwater vegetation, or even a little tree branch, a low pressure area is created immediately in front of the blades. The prop can literally boil the water, creating bubbles, so once again the prop is pushing air. When the bubbles collapse they can cause pitting on the prop, sometimes it looks like scorch marks. Damage to the lower unit or prop, or something caught on the boat right in front of the motor can cause that as well. You might have caught some seaweed on the boat or motor that dropped off before you got back to the marina.

3. spun hub: the prop has a rubber bushing built in, to absorb the shock of shifting and possible collisions with underwater obstructions. It can wear out and start slipping. Paint or scribe a mark across the inner and outer hubs, put the boat in the water and run at full speed for a little while, then if your marks are no longer aligned, the hub is spun. Any prop shop can fix it for a reasonable charge.

我怀疑是2，因为几分钟之前我刚经过一片水草比较多的地带然后就忽然觉得船尾声音有点不一样。现在的问题是不知道是否是暂时性的，还是需要修理。后来直接就上岸了，没再试。

把上面的答复贴出来，估计也许您也有兴趣知道。

祝好。

所有跟帖： 

• 谢谢！和我猜的差不多，问题出在螺旋桨上。 -史迷- ♂ (49 bytes) () 06/26/2012 postreply 10:08:05