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jwroblew
05-14-2008, 02:05 PM
I'm getting a little vibration during my hole shot when pulling a skier. After the boat is almost on plane the vibration is totaly gone, and stays gone during cruise. What should I be looking at, alignment issues? Since I don't get it all the time I would not think it is prop related, and I just had it reworked anyhow. Any thoughts would be helpful.

jkski
05-14-2008, 02:09 PM
If you just had the prop re-worked and the issue did not exist prior, that is exactly where I would start looking as you may be dealing with an issue of not being properly balanced.
Also, if you just had the prop re-worked, something must have happened (ie. did you accidentally hit something submerged), s you may need to check the shaft and strut for alignment issues.

jwroblew
05-14-2008, 02:17 PM
Forgot to mention, there was a vibratin before the prop got reworked. The strut looks straight, no uneven ware, the shaft is centered in the hole in the hull. The boat has always done it since I got it new. Never thought anything of it untill I got in a new one the other day, it had no vibration what so ever. Maybe it's me being OCD

MDuncanAU
05-14-2008, 02:22 PM
A buddy of mine had the same exact problem with his Tige. Turns out that his prop must have hit the smallest of logs, but it did enough to bend one of the fins. They said that even the slightest knick in a prop can cause massive vibration, which are especially noticed during slow speeds. Once the speed picks up the vibration goes away (I don't know why) and the boat runs smooth.

djhuff
05-14-2008, 02:36 PM
Even if you have the prop re worked, it won't be the same as new.

Whenever I put a reworked prop on my boat, I have a very slight vibration that only shows up under load. Put a new prop on, problem went away. The more I pay attention, I think everyone's boat vibrates a little on a refurbed prop, but you just don't notice it for one reason or another.

See if you can get your hands on a brand new out of the box prop and try that.

jwroblew
05-14-2008, 03:30 PM
I looked at a new prop, but man are the splined props expensive. I did notice that the shaft has some for and aft play, all inside the coupling at the trans. Is that normal for the splined shafts? I know the old keyed and teppered shaft had no play.

jkski
05-14-2008, 03:44 PM
I looked at a new prop, but man are the splined props expensive. I did notice that the shaft has some for and aft play, all inside the coupling at the trans. Is that normal for the splined shafts? I know the old keyed and teppered shaft had no play.

Just notice you are in the Toledo, Ohio area. I am going to be pulling a brand new 3-blade 12x13 prop off my 2008 and replacing it with a 4-blade, so I will have a spare prop if you want to try it. You would not want to use it for skiing the course, as you'd need to re-cal your PP, etc., but just as a test to rule out a prop it would do the trick.
Let me know and we could figure something out.

east tx skier
05-14-2008, 03:56 PM
If you still have a traditional shaft stuffing box, you might want to check that as well. My brother in law's boat had an intermitent vibration issue that was resolved by repacking the stuffing box.

TX.X-30 fan
05-14-2008, 04:09 PM
I bent all three blades at Mcqueeny few years back and had no vibration at all. I find it hard to believe its in the prop. Had a Blade last year take a submerged log and slightly fold it down and never even knew until I pulled it out and looked close.

Just a thought but could it be coming from the rudder, something back there loose. Good luck.

jwroblew
05-14-2008, 04:16 PM
Replaced the stuffing box 2 years ago with a dripless.

JKSKI I will send you a PM, I hope we can work something out.

ShamrockIV
05-14-2008, 04:17 PM
might have bent the shaft a hair!!! it does not take much to cause vibration under a load

jwroblew
05-14-2008, 04:19 PM
what about the for aft play, is this normal?

Hollywood
05-14-2008, 05:43 PM
Sounds like prop to me.

gigem75
05-15-2008, 01:06 PM
When was the last time you checked the shaft alingment? how bout the damper plate?

jwroblew
05-15-2008, 11:56 PM
I was going to check the alignment this weekend. Does anyone know the specs?

Never even thought about the damper plate, I had one go bad on my old '79 stars and stripes, but that was after a pretty big interference problem I had with a log, my prop and the bottom of the boat.

johkur
02-28-2009, 11:40 PM
Also a vibration issue: I've got terrible vibration, but mostly in neutral. Its an L18, the dealer says the vibration is due to the size of the engine, but I've been in other 8.1L boats, even smaller ones than the X-45, and they don't vibrate like this. I ruled out props and shafts since the problem happens in neutral, and when you get underway you either don't notice it or it goes away. But sit near the stern of the boat or on the platform when in neutral, and the vibration is petrifying, like the boat should fall apart. Happens when the engine is warm or cold, doesn't matter. Boat is still under warranty, so dealer keeps telling me not to worry, but I really don't like having the problem. I had to wedge lots of pads in the metal door to the bow, since that really was making a racket in neutral as well.

Any ideas where the dealer should look?

JimN
02-28-2009, 11:46 PM
johkur- have them make sure it's firing on all cylinders. Unless the exhaust note is that low, you shouldn't have that much vibration.

johkur
03-01-2009, 01:15 PM
They did pull all the plugs and send photos to mastercraft, and the plugs all looked the same. In fact, they then changed the plugs, and the vibration got much worse, but they believe that its not the plugs. Compressions were close across all cylinders as well. How else they should test its firing on all cylinders?

Also, what do you mean about 'exhaust note is low'? Before I got the boat, they retrofitted 2 silent masters and removed the obstructed tips. So the tips don't have flaps and are totally open, and the 2 silentmasters are in the engine compartment. I had originally expected one big silentmaster, which I think would have helped noise and vibration even more, but that is no longer what Mastercraft sells when you buy silentmaster. I would have to think that all the European boats that have silentmasters and other silentmaster customers in US would be complaining about vibrations this severe if they were the cause. Unless maybe there was a retrofit installation issue. Maybe the tips are supposed to have some gasket that absorbs vibration?

Thanks.

Footin
03-01-2009, 01:42 PM
Did they check all the plug wires?

JimN
03-01-2009, 03:49 PM
They did pull all the plugs and send photos to mastercraft, and the plugs all looked the same. In fact, they then changed the plugs, and the vibration got much worse, but they believe that its not the plugs. Compressions were close across all cylinders as well. How else they should test its firing on all cylinders?

Also, what do you mean about 'exhaust note is low'? Before I got the boat, they retrofitted 2 silent masters and removed the obstructed tips. So the tips don't have flaps and are totally open, and the 2 silentmasters are in the engine compartment. I had originally expected one big silentmaster, which I think would have helped noise and vibration even more, but that is no longer what Mastercraft sells when you buy silentmaster. I would have to think that all the European boats that have silentmasters and other silentmaster customers in US would be complaining about vibrations this severe if they were the cause. Unless maybe there was a retrofit installation issue. Maybe the tips are supposed to have some gasket that absorbs vibration?

Thanks.

I think you answered your own questions. Since the SilentMasters are in the engine compartment, open it and if the noise level increases dramatically, that's where it's coming from. Once that sound goes into the closed compartment, it has no choice but to make things resonate. If you were to shoot a video of the exhaust and slow it down drastically, you'd see that the walls flex every time it gets an exhaust pulse.

JimN
03-01-2009, 03:50 PM
Did they check all the plug wires?

I think that has coil-near-plug, so they're really short. I would like to find out if it's getting consistent 'fire' signal from the ECM but I'm pretty sure the noise is from the exhaust.

johkur
03-01-2009, 04:58 PM
We're not getting alot of 'noise' though, just the whole boat is shaking and rattling.
I know someone said to me that the boat felt like it was 'missing', but they said each spark plug had about the same deposits on each, so that it meant they were all firing. And after they changed the plugs, it did get worse, so I guess maybe I have to wait till we put it back in the water, and then have them check the wiring/etc.
Since the vibration is so much worse at slow speed than higher speed, I have to think its not the silentmasters, but more the engine itself. If I have it in neutral and give it more gas, the vibration subsides rather than gets worse.

Thanks.

JimN
03-01-2009, 08:10 PM
Well, if you think about it, as long as it's not in gear, it can't be the strut, prop or prop shaft. If the noise isn't excessive when you open the motor box and the exhaust is directed out through the transom, it has to be the motor. Something is either not firing correctly (like the plugs are bad- and did they have a bulletin about that?) or something is badly out of balance. Have the motor mounts been checked? Can you put your hand on the motor when this is happening and feel major vibrations? Has the tech done much testing or is it more like standing and scratching their heads? EVERYTHING that causes a symptom can be diagnosed, period. As long as it's not intermittent, it's just a process of elimination.

"but they said each spark plug had about the same deposits on each, so that it meant they were all firing."

Or, missing with the same regularity. Looking at spark plug deposits and deciding that it's not missing is like looking at the impeller and saying that it has never run hot. The two aren't valid. The only way to know if it's not missing is to check for ignition events. That takes timing lights, spark testers, SUN or other diagnostic equipment, not looking at spark plugs.

pbloss
03-01-2009, 09:01 PM
Hole shot should be smooth as silk, Any ding in blade, replace it. Refinished blades are a wast of money. The least amount of vib is a no no! Call Lex Pearson at Rambo Marine and ask him some questions. He is the MasterCraft guru. Trust me I have no ties with rambo marine and I trust this guy with my 1988 mint vintage boat.

Pat