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View Full Version : How much vibration is reasonable in idle, and how many repeat fixes?


johkur
06-26-2009, 04:29 AM
1) My 2008 X45SS has vibrated like crazy since the start. There's rattling from multiple places on boat. They've checked the timing, the plugs, the software upgrade, the motor mounts, and believe that 8.1L engines just shake alot in idle. All last summer the boat was losing antifreeze, and they discovered that both exhaust manifolds were cracked. They told me that fixing that might address the vibration, I gave them the benefit of the doubt, but again this year, the boat vibrates even in neutral and doesn't seem to smooth out until about 2500rpm (even in neutral). What else to look at besides the lemon law? The dealer is going to send Indmar a video, but I'm really wondering what people on this forum think an 8.1 adds to the 'vibration index' or how to measure it?

2) Also, I have two silentmasters and straight thru stainless tips, without baffles or flappers. Might have going in reverse sent cold water up and possibly caused the exhaust manifold cracks? Indmar said they had no idea why 2 manifolds would both have cracks other than a bad manufacturing batch, but I'm still wondering if history is about to repeat itself. MC said that the Silentmasters prevent water from backing up, but I don't see how baffles would do that if you're in reverse hard or long.

3) And my attitude plate computer used to not show the level on the VDIG, so at the end of last season the attitude plate computer behind the steering wheel was replaced. It worked that week before the dealer winterized the boat, but this year, the attitude plate doesn't even go up and down, and now MC has the old computer. Boat has been at shop a couple of days so far on that one now for troubleshooting, I really need the plate to prevent porpoising at higher speeds.

4) And my KGB kept filling while boat was off, so they flipped the pump or something like that, but that didn't solve it at end of last year. So I found out about the green impellers on this forum, told them about it, they swapped it this Spring before 1 year warranty expired (although it was really a reported issue from last year), they replaced the impeller, it seemed to fix the problem, but they told me to pay $40 for the impeller pending future MC approval. Wouldn't that be under warranty? But for those who have wondered about kgb fills, the green impeller did help.

That the attitude plate controls are so unreliable is a pain, but I'm really worried that I'm going to crack manifolds again, and I'm really bothered by the excessive vibration, the noise in the dash from it even at idle, the door to the bow was ridiculous until I wedged a bunch of pads in there, but an idle boat shouldn't feel like you're sitting in the last row of an old bus. I've been on other non-MC 8.1 boats and they're nothing like this. I'm told "its a heavy engine" but it really seems like something is still wrong.

These weren't the only problems, but the ones still lingering this season, and I'm really getting tired of having the boat at the shop and still not right afterwards. Any ideas?

JimN
06-26-2009, 09:11 AM
1) My 2008 X45SS has vibrated like crazy since the start. There's rattling from multiple places on boat. They've checked the timing, the plugs, the software upgrade, the motor mounts, and believe that 8.1L engines just shake alot in idle. All last summer the boat was losing antifreeze, and they discovered that both exhaust manifolds were cracked. They told me that fixing that might address the vibration, I gave them the benefit of the doubt, but again this year, the boat vibrates even in neutral and doesn't seem to smooth out until about 2500rpm (even in neutral). What else to look at besides the lemon law? The dealer is going to send Indmar a video, but I'm really wondering what people on this forum think an 8.1 adds to the 'vibration index' or how to measure it?

2) Also, I have two silentmasters and straight thru stainless tips, without baffles or flappers. Might have going in reverse sent cold water up and possibly caused the exhaust manifold cracks? Indmar said they had no idea why 2 manifolds would both have cracks other than a bad manufacturing batch, but I'm still wondering if history is about to repeat itself. MC said that the Silentmasters prevent water from backing up, but I don't see how baffles would do that if you're in reverse hard or long.

3) And my attitude plate computer used to not show the level on the VDIG, so at the end of last season the attitude plate computer behind the steering wheel was replaced. It worked that week before the dealer winterized the boat, but this year, the attitude plate doesn't even go up and down, and now MC has the old computer. Boat has been at shop a couple of days so far on that one now for troubleshooting, I really need the plate to prevent porpoising at higher speeds.

4) And my KGB kept filling while boat was off, so they flipped the pump or something like that, but that didn't solve it at end of last year. So I found out about the green impellers on this forum, told them about it, they swapped it this Spring before 1 year warranty expired (although it was really a reported issue from last year), they replaced the impeller, it seemed to fix the problem, but they told me to pay $40 for the impeller pending future MC approval. Wouldn't that be under warranty? But for those who have wondered about kgb fills, the green impeller did help.

That the attitude plate controls are so unreliable is a pain, but I'm really worried that I'm going to crack manifolds again, and I'm really bothered by the excessive vibration, the noise in the dash from it even at idle, the door to the bow was ridiculous until I wedged a bunch of pads in there, but an idle boat shouldn't feel like you're sitting in the last row of an old bus. I've been on other non-MC 8.1 boats and they're nothing like this. I'm told "its a heavy engine" but it really seems like something is still wrong.

These weren't the only problems, but the ones still lingering this season, and I'm really getting tired of having the boat at the shop and still not right afterwards. Any ideas?

There's no reason for it to vibrate that much. Think about the last time you were in a GM vehicle with a lumpy feeling engine- they haven't had one in 40 years. These usually idle very smoothly and your dealer needs to look at it correctly. Use a timing light to verify that each plug is getting the signal to cause spark and check the plugs for evidence that one or more isn't firing. It should still be under warranty and they need to fix this.

wakedoc
06-26-2009, 11:33 PM
That vibration shouldn't really be noticable.
On another slightly related note, I have an 09 X1 with MCX, and right from the start it has had a vibration at idle, getting worse at 1200. The vibration has been bad enough to shake the tower and windshield. Computer checks out fine, replaced some of the injectors and it is now only about 1/10th as bad as it was. Aiming to clean the remaining injectors in the next week or so - will update you as to whether this clears the issue.