Vibration or chatter in Steering

[smokedog2]

When I was out with my LSV towing a tube I could yank the steering to throw the tube into a slide out of the wake. By leaning the boat over and pulling around the sound of the boat would change, this is the prop running in the wash off the bottom of the boat which is an air/water mix. Once you put it down the noise goes away.

That is what I found anyway. I filled the center sac and never heard the prop again.

Generally running a prop in air or air/water is bad. At leat that is MHO.

SD2

[Shoemaker Mobius]

Smokedog,
Is what you are describing called cavitation? I have read threads on other BBs that indicated under various conditions and different boats, cavitation can be a real problem, but I don't really know or understand what it is.

[smokedog2]

Yep, one type of cavitation. It can also be caused by poor prop selection, poor trim on an o or I/O, wrong prop for weight etc. My 40 hp Honda will cavitate at top end when empty. The prop is designed to move three guys, two dogs a layout boat and 150 decoys so it "cuts" more. I am no expert but the Board boat is not designed to yank & bank empty. Just add a little weight to keep the prop in the water.

I think porposing is also a form of cavitation.

Where the heck is Brian, he would know better than I would.

Ha I see Brian is still at work - what is your $.02 at this late hours? I will find out tomorrow


SD2

[Brian Raymond]

The "chatter" that is felt is caused by turbulent water passing the rudder under certain conditions. This will vibrate the cable inside the sheathing up to the rack at the helm. This makes the gear mesh between the helm and cable also vibrate. This is common on the rack steering system. Brian Raymond

[clark]

Brian,

I spoke to you last week about this happening on my 05 LSV. Took it to the dealer and they checked everything and said the exact same thing in your last reply. They said turbulent water passing the rudder. My dealer did a great job. Took in on Thursday and they were so busy they could not fit me in, however, they stayed late on Friday. I spoke with the service manager at 8:00PM and they had mine ready so I could pick it up on Saturday.

Great job Atlanta Marine. Kurt and Lisa run a great dealership. Thanks to Brian (not Brian Raymond), their service Mgr for fairly quick turn around.

Now, I also give a big thanks to Brian Raymond for speaking with me on the phone last week to help me understand everything that was going on. Oh yeah, one problem they could not replicate is my trailer shakes from side to side at approximately 25-30 MPH. Anyone else having this problem? Other than that, it is a Great Boat.... 05 Mobius LSV.

Thanks Guys.

Clark

[pecanflyboy]

The "chatter" that is felt is caused by turbulent water passing the rudder under certain conditions. This will vibrate the cable inside the sheathing up to the rack at the helm. This makes the gear mesh between the helm and cable also vibrate. This is common on the rack steering system. Brian Raymond

I was in the process of starting a new thread, when I found this one in a search. I'm having the same problem.

Background: 125 hours, 2001 Mobius. Just replaced the steering cable with the Teleflex SSC15418 (I'd recommend the SSC15419 19' cable, as the 18' cable was 10" shorter than the one installed). This cable makes the steering feel like butter...very nice.

Condition: Full throttle, loaded boat, rudder near center. Turbulence or cavitation on the rudder is transmitted from the rudder, to the cable, to the rack, and into the helm. I can actually feel the vibration in the cable when I reach beneath the dash. It feels like a rattle or chatter.

Causes?: It may be just the cavitation, as Brian has said, and it may be normal. However, it is unnerving. I worry that there is too much slop or play in the steering cable clamp block and/or in the clevis where the cable attaches to the rudder control horn. I was able to replicate the feel by moving the clamp block against it's stops where it hits the cast mounting. I don't know if this is what I'm feeling in the helm, or if it is just a vibration coming up from the rudder.

Can anyone confirm that this is a normal condition? I really don't want to spend the $$ on a new clamp block and clevis only to find out that it's not a problem.

Jimmy

[pecanflyboy]

https://forum.moomba.com/showthread.php?t=14645

This was the thread I'd created about replacing the steering cable.

[deafgoose]

Check how much "play" you have in your clamp block. Mine needs to be replaced also.

[pecanflyboy]

Check how much "play" you have in your clamp block. Mine needs to be replaced also.

There isn't much "play" in the ball and block, other than it's ability to rotate freely around the ball.

[saskie99]

Last summer I had the same problem, it was a slightly bent prop and the locking nut had slid down the shaft and prop was not super tight on the tapered shaft. I put a rebuilt prop on and all my problems went away once it was seated properly on the drive shaft.
It my sound like I negected my boat but is sits on a lift and I never had it on a trailer all summer so I was just something I never thought to check.