1994 2000SC 4.3 Alpha Drive Steering problems

[9Ball]

At low speeds Steering would hunt back and forth... it was not the wind or current Cruising was perfect no problems it would stay on course..... anyone have a idea what I should check?

Todd

[jrings]

I wouldn't check a thing... This is very common. Although if it is excessive something may be wrong but it is very typical.

[CountryME]

I second jrings comment. What you are experiencing at low speeds is a fluid dynamic phenomenon known as vortex shedding. If you want to make it go away invest in a set of SmartTabs. Added them to my boat and the hunting went away.

-JP

[seapuppy]

vortex shedding???..nnnneeeever heard that one.....what I think he's experiencing is "bow wander"....typical for a single drive going slow where the drive is trying to push the bow out of the way....learn to correct slightly with the wheel and if you have tabs...put those all the way down...also put your drive down ..this will help reduce but not eliminate "bow wander".....


:arr arr

[ss3964spd]

Ditto - mine wanders too.

At slow speeds stern drives don't respond immediately to steering inputs so practice small corrections. Because of the slow reaction there is a tendency to over correct.

I have hydro tabs on mine. Putting them down all the way does help but does not eliminate it.

Dan

[9Ball]

Hmmmmmm OK, But with boat on the trailer and engine NOT running.... I can grab the outdrive Leg, and move it back and forth 3 to 4 inches, and the stering wheel don't move.... is that normal. just seemed like ALOT of "Free Play" to me.

Todd

[CountryME]

SP, Check out this site: http://www.mecaenterprises.com/vortex_shedding.htm It gives an explination of vortex shedding. If you look over the back of your boat at slow speeds you may even see the oscillating vorticies coming off the stern.

9Ball, I agree with you, that seems like alot of free play. Do you have power steering or mechanical?

[ss3964spd]

3 or 4 inches with no wheel movement?

That's a little different, but with power steering you might not see much movement. Time to check the linkage with a helper. Have him/her move the wheel left and right while you look at the linkage. It could be the rack behind the wheel, the cable connection to the linkage, the linkage itself, or where the linkage attaches to the drive.

[seapuppy]

hmm...that does sound like a mess of free play on the drive...you might need to go inside and check the rack and pinion steering arm...see if it's extremely worn...

vortex shedding really doesn't apply with fluids and boats......http://en.wikipedia.org/wiki/Vortex_shedding

it mainly applies to poles or buildings in turbulant air....boats don't usually exibit this phenomina ...what your probably seeing behind your boat is eddy turbulance from the props making swirling formations of water.......

what he's experiencing is bow wander..

SP

[9Ball]

I have Power steering... I'll have to check it out Tuesday evening.... I'll report back the findings...

Todd

[9Ball]

I have always noticed oscillating vorticies coming off the stern. Didn't think it was a big deal. Mostly from the prop I figured.

Todd

[9Ball]

Originally Posted by seapuppy

hmm...that does sound like a mess of free play on the drive...you might need to go inside and check the rack and pinion steering arm...see if it's extremely worn...

vortex shedding really doesn't apply with fluids and boats......http://en.wikipedia.org/wiki/Vortex_shedding

it mainly applies to poles or buildings in turbulant air....boats don't usually exibit this phenomina ...what your probably seeing behind your boat is eddy turbulance from the props making swirling formations of water.......

what he's experiencing is bow wander..

SP

I checked The Rack and Pinion, Everything is Tight.... no end Play (Axial or Radial), So I guess it normal.... The Piston does go in and out as the Leg is moved (3 or 4 inches)(but the Steering Wheel doesn't move (if I move the LEG more than 3-4in then the Steering Wheel will move)

Todd

[mcoffey]

Originally Posted by seapuppy

hmm...that does sound like a mess of free play on the drive...you might need to go inside and check the rack and pinion steering arm...see if it's extremely worn...

vortex shedding really doesn't apply with fluids and boats......http://en.wikipedia.org/wiki/Vortex_shedding

it mainly applies to poles or buildings in turbulant air....boats don't usually exibit this phenomina ...what your probably seeing behind your boat is eddy turbulance from the props making swirling formations of water.......

what he's experiencing is bow wander..

SP

Hey SP, ran across this article today. It was sent in an iBoats email that I normally delete but it caught my eye

http://www.iboats.com/review_monthly..._article2.html

Seems CountryME is dead on here with Vortex Shedding as the cause


Still does not help Todd with his 3 to 4 inches of free play, sorry about that.

[9Ball]

Originally Posted by mcoffey

Hey SP, ran across this article today. It was sent in an iBoats email that I normally delete but it caught my eye

http://www.iboats.com/review_monthly..._article2.html

Seems CountryME is dead on here with Vortex Shedding as the cause


Still does not help Todd with his 3 to 4 inches of free play, sorry about that.

One of the things that it talks about is "Put the tabs down. If you have trim tabs, try putting them down all the way. These can act as horizontal stabilizers to keep the stern from wagging. "
my other boat had smart Tabs and it didn't have this problem, but this boat does not have Tabs sooooo another reason I should get some smart tabs..lol when I have the budget $$$

WOW Who Knew!!!! LOL

Thanks SP and Country ME

Todd

[ss3964spd]

Don't plan on tabs eliminating the problem Todd. I've got hydro tabs on mine and, while they do help a bit, it still wanders around.

I just learned to give it very small corrections.

Dan