沒有轉速表。我上網問了一下，這是一個比較明白船的人的回答。

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.

我懷疑是2，因為幾分鍾之前我剛經過一片水草比較多的地帶然後就忽然覺得船尾聲音有點不一樣。現在的問題是不知道是否是暫時性的，還是需要修理。後來直接就上岸了，沒再試。

把上麵的答複貼出來，估計也許您也有興趣知道。

祝好。

所有跟帖： 

• 謝謝！和我猜的差不多，問題出在螺旋槳上。 -史迷- ♂ (49 bytes) () 06/26/2012 postreply 10:08:05