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Low speed side to side shimmy. Normal?

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TBagTom

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On my 2000 XP when I'm cruising in the 20-30mph speedo indicated spot my boat does this weird side to side shimmy. It will slide left and feel almost like it hits something then slide back over right and again feel like it "hits" then go back to the left and continue on etc etc.

It does not do this when i am above or below the speedo indicated 20-30mph range. It also does not seem to do it when the water is really smooth.

Is this normal?

I also have a SeaRay 20' bow rider that will do the same side to side shimmy at low speeds so I'm thinking it might be somewhat normal. What do you guys think?
 
It doesn't sound normal to me, and honestly I'm at a loss to tell you what the problem is. Check your sponsons make sure they're tight to the hull, maybe the motor mounts.

Lou
 
It doesn't sound normal to me, and honestly I'm at a loss to tell you what the problem is. Check your sponsons make sure they're tight to the hull, maybe the motor mounts.

Lou

The jet feels solid when I turn it left to right by hand. The bars move perfectly with it.

Can the steering cable possibly be stretching causing the boat to turn left and right on its own at slow heavy load speeds?
 
Check the steering cable fitting where it comes through the ride plate, the parts diagram doesn't show it very well, also make sure the cable is secured at both ends. The ski tends to turn to the left you can compensate for this by adjusting the cable end where it attaches to the steering nozzle. Try taking a look in the service manual, you can download one from this site if you join as a premium member or just google for one.

http://partsfinder.onlinemicrofiche...=13&make=seadoopwc&a=259&b=19&c=0&d=-STEERING

Lou
 
I just adjusted the steering cable because my handlebars were to the left. I did the cheater way though I didn't use the adjustment nut.
 
What do you mean when it "hits" something? Is it something you can feel or hear? It almost sounds like your not going quite fast enough to fully plane on top of the water so the hull zig zags as it cuts through. It should be a pretty smooth back and forth slip/slide though, no jerks or hitting anything. The stock speedos are way off so your not going anywhere as fast as it says.
 
On my 2000 XP when I'm cruising in the 20-30mph speedo indicated spot my boat does this weird side to side shimmy. It will slide left and feel almost like it hits something then slide back over right and again feel like it "hits" then go back to the left and continue on etc etc.

It does not do this when i am above or below the speedo indicated 20-30mph range. It also does not seem to do it when the water is really smooth.

Is this normal?

I also have a SeaRay 20' bow rider that will do the same side to side shimmy at low speeds so I'm thinking it might be somewhat normal. What do you guys think?

Sounds like a wild ride to me! :) I bet you're describing the speed at which the hull is about to plane. I don't intentionally operate around that speed, either higher or lower but not on the knee point.
 
When I say it "hits" it feels like it slides and something in the back jerks and clanks then it slides the opposite way and does the same thing.

I took it out after a storm today. The lake was glass and there was zero wind. It was doing a side to side shimmy at three quarters throttle as well. It was kind of scary. It felt almost like it wanted to buck me off.
 
Wow man 3/4 throttle you should be well on plane and moving in a straight and deliberate direction.

I wonder if your ride plate screws are lose, missing or some hardware like that, dragging under the hull or shifting around acting like a rudder?
 
What you are describing sounds a lot like chine walk. The chines are the raised strips on the bottom of the hulls and they can actually cause the symptoms you are0 describing if they are not true. The old standups and especially the first kawaesaki 750 SX's were notorious for this and were almost scary. However I have never seen this on the seadoos especially the XP's. Have someone hold the bars while you try to move the steering nozzle there should not be any play. Also make sure the ride plate, intake grate and sponsons are tight. The only other thing I can suggest as a last resort is to true the hull. The easy way is to sand the hull from front to back in one continuous motion with 80 grit paper. The hull will look like crap though. To do it perfectly you have to actually block sand the bottom perfectly flat like prepping a car for paint. The seadoo racers handbook details the procedure.
 
The sponsons are tight. I'm going to get under there right now and check everything out.

The jet nozzle has a little play in all directions. Like maybe a couple millimeters. I don't see how that could be messing things up though.
 
I don't think it's even possible for your reverse gate to be dragging since you're moving forward but I dunno, make sure it's well up above and out of the nozzle when in forward position.
 
What you are describing sounds a lot like chine walk. The chines are the raised strips on the bottom of the hulls and they can actually cause the symptoms you are0 describing if they are not true. The old standups and especially the first kawaesaki 750 SX's were notorious for this and were almost scary. However I have never seen this on the seadoos especially the XP's. Have someone hold the bars while you try to move the steering nozzle there should not be any play. Also make sure the ride plate, intake grate and sponsons are tight. The only other thing I can suggest as a last resort is to true the hull. The easy way is to sand the hull from front to back in one continuous motion with 80 grit paper. The hull will look like crap though. To do it perfectly you have to actually block sand the bottom perfectly flat like prepping a car for paint. The seadoo racers handbook details the procedure.

I'm leaning this direction, and I've actually felt it before on my XP and XPL, but never at 3/4 throttle, usually at like 7-10mph so i'm little reluctant to say... "spot on diagnosis"

I'd also suggest checking the ride plate and intake for snugness, and of course the steering tightness.

But I've most definitely felt this before, but usually just a little pop on the throttle alleviated the issue.

If its happening all the time, i'm at a loss except for the above suggestions.
 
If you trim the nose way down it can kind of wander, but it should go away with neutral or up trim.
 
Haha. I was going to say that.

I went under it while it was on the lift. Everything is tight and straight.

I just took it out again though. It seems sporadic as to when it does it. When it does happen though I feel a clunking coming from the jet/pump area.

I did notice though when coming off plane from speed it really wobbles left and right hard until it comes off plane.

I put it away for the day, but I'll try to take some videos of it happening next time I take it out.
 
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I think I'm just for shits going to replace the steering cable. How difficult is this? Does anyone have a write up on it?
 
replacing the cable if it passes the hand/eye test seems to me like a good way to piss away $90.

I'd rather buy a martini and two lapdance's with that money.

Granted I still can't say what's causing the issue, so maybe i'm way off base, or I like boobies too much

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I also have a SeaRay 20' bow rider that will do the same side to side shimmy at low speeds so I'm thinking it might be somewhat normal. What do you guys think?
nmost boats will wander left right while going straight ad headway speed \but ive never seen it at 20 - 30
 
My 00 gti doesn't slide left to right but it starts to rock from side to side, it seems to get worse with speed. I'm still trying to sort things out on it and always slow down when it rocks enough to get scary. The dealer says its normal, maybe its a seadoo thing, i've never experienced on the yamahas i've ridden. I have an issue where at about quarter throttle the engine wants to die but more throttle will get the engine to overcome this and rev higher. I'm guessing it is the low jet losing flow and the high one taking over with more throttle. This is the time/speed that the rocking starts. It leans pretty far over when the rocking happens. Both sponsons are there and secure.

Also as my speed increases the ski seems as if it can't turn to the left.
 
My 00 gti doesn't slide left to right but it starts to rock from side to side, it seems to get worse with speed. I'm still trying to sort things out on it and always slow down when it rocks enough to get scary. The dealer says its normal, maybe its a seadoo thing, i've never experienced on the yamahas i've ridden. I have an issue where at about quarter throttle the engine wants to die but more throttle will get the engine to overcome this and rev higher. I'm guessing it is the low jet losing flow and the high one taking over with more throttle. This is the time/speed that the rocking starts. It leans pretty far over when the rocking happens. Both sponsons are there and secure.

Also as my speed increases the ski seems as if it can't turn to the left.

If that's a carbed motor you need to take care of that lean spot right away or you're liable to roast a piston. Any 2-stroke for that matter, will roast a piston if running lean like that.
 
I just took it out again in pretty calm water. There's a definite "jerk" in the back that I can feel. Can the driveshaft be loose or something causing the prop to jerk around in a weird way?

Like, can there be shaft play causing the prop to bounce on the wear ring? I just had a new wear ring put in.
 
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