Knocking Noise/Lack of Power

[bmo]

I have a 2003 Four Winns 268 Vista with a 350 Mercruiser BravoIII. I can hear a slight knocking noise coming from the out drive when its idling. You can not hear the noise in the engine compartment. Also, when I push the throttle the boat accelerates fine until about 2400 RPMs then it bogs a little bit and does not acclerate anymore. The motor sounds good and there doesn't seem to be anything leaking. The lower unit fluid is fine as well. Any thoughts of what this could be?

 

[HT32BSX115]

Re: Knocking Noise/Lack of Power

Knocking noises are sometimes the gimbal bearing and/or U-joints. does it change if you turn the drive left to right/up/down while at idle?

Have you ever had the drive off to check the bellows/U-joints? Have you ever had the drive oil changed and inspected?

 

[bmo]

Re: Knocking Noise/Lack of Power

No, the noise doesn't change when I move the drive; it's constant. I haven't had either the bellows or the u-joints checked.

I did the summerization myself in the spring...changed the oil and lower unit fluid. Nothing looked out of the ordinary. I asked a guy in the service department at my marina...without looking at it he thought maybe the prop hub or engine coupler....?? Hopefully I get someone out to look at it this week but I was hoping someone here might have some insight.

 

[HT32BSX115]

Re: Knocking Noise/Lack of Power

Couplers usually don't make a lot of noise. It sounds more like a gimbal bearing or U-joints.....It's a Bravo III, You don't have a "Prop Hub"


Does it do it in gear or neutral or both? Did you buy this boat new? and have you ever had the drive off?

 

[bruceb58]

Re: Knocking Noise/Lack of Power

When was the last time the drive was pulled?

 

[John Evans]

Re: Knocking Noise/Lack of Power

I have about the same issue. My wife says it sounds like beer cans bouncing around down there. Idles fine, out of gear runs @ 3-3.5k rpm smooth, good oil pressure and engine temp. In gear she makes the noise and looses power around 3k. Any ideas?

 

[Haut Medoc]

Re: Knocking Noise/Lack of Power

I have about the same issue. My wife says it sounds like beer cans bouncing around down there. Idles fine, out of gear runs @ 3-3.5k rpm smooth, good oil pressure and engine temp. In gear she makes the noise and looses power around 3k. Any ideas?

You should start your own thread & describe your particular symptoms....
& make, model, serial #..........