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Vibration at low speeds
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Author:  schoolsOut [ Thu Oct 03, 2013 7:49 pm ]
Post subject:  Vibration at low speeds
I tend to get a vibration in my 210 horizon when making a hard turn while on the throttle at low speeds. For example, if a skier/wake boarder falls and I cut the engine, when I give it gas and turn it hard around, I can feel a vibration throughout the boat. Is this normal? It seems to happen under any circumstance in which I accelerate and turn hard below planing speed. While on plane, I do not notice the same problem. I have a 3-blade stainless prop which may have a slight ding in one blade (which I will try to get a picture of this weekend). I am not sure if that could cause the vibration. Maybe it is nothing and I am just being obsessive. Thanks in advance for your help.
Author:  Walt [ Thu Oct 03, 2013 9:06 pm ]
Post subject:  Re: Vibration at low speeds
In general, avoid turning to the stops with power. Sounds like a gimbal bearing to me. Should be checked about every 5 years anyhow, and not expensive as I recall. Just had mine checked over last off-season.
Author:  schoolsOut [ Thu Oct 03, 2013 9:14 pm ]
Post subject:  Re: Vibration at low speeds
Walt wrote:
In general, avoid turning to the stops with power. Sounds like a gimbal bearing to me. Should be checked about every 5 years anyhow, and not expensive as I recall. Just had mine checked over last off-season.


Thanks for the reply. I don't turn it to the stops. Just a carving turn at low speeds creates the vibration. I am guessing the gimbal bearing is original. I have only had the boat for two years and have not had the drive off yet. I guess I should pull it in the spring and check the u-joints, bellows, and the bearing.
Author:  LouC [ Fri Oct 04, 2013 12:52 am ]
Post subject:  Re: Vibration at low speeds
Do you know if the drive was taken off and the ujoints and gimble bearing inspected before you got it?
If I was feeling vibs I would getvthebprop checked out but I'd also remove the drive at the end of the season rather in the spring. If there is water in the bellows it will sit there rusting the input shaft where the seal rides for months.
Author:  taz42169 [ Fri Oct 04, 2013 4:24 am ]
Post subject:  Re: Vibration at low speeds
+1 on that gimbal bearing. Pulled my drive this year and I had water in my bellows. Small tear which permitted water leading to vibration. My gimbal bearing was getting rough and was causing my vibration. Also +1 on what Lou said, sent my props out for a tine up.

Luckily, it's the end of the season...pull that drive!
Author:  schoolsOut [ Fri Oct 04, 2013 3:55 pm ]
Post subject:  Re: Vibration at low speeds
Just looking over old emails from the previous owner. He replaced the bellows in the summer of 2009 and the gimbal was replaced at some point under warranty. I am going to pull the drive this fall as recommended. I really have no idea what I am doing with all of this; it is my first time, so be gentle with me. My dad is a lifelong auto mechanic so obviously knows his way around wheel bearings and u-joints and I'm sure he will supervise. I plan to replace pretty much all the "regular maintenance" stuff: bellows, u-joints, gimbal bearing.
Anything I am forgetting?
I have read (I think on this forum) that the u-joints are just regular automotive u-joints. Is that correct?
Any suggestions on where to get a gimbal bearing and bellows? I'm sure that I can find Sierra hardware at all of the obvious places. Is that what I want?
I am just hoping to do the job right the first time and be all set for the next couple of years. I do also have some corrosion on my outdrive for some reason even though it is a fresh water boat and always has been. I am looking into getting that refinished while it is off. Like I mentioned earlier, I have a slight ding in the prop which I could get repaired, I just have to find a reputable prop shop. That is easier said than done in Lancaster County, PA. Thanks again for all the expert guidance. For what is worth, by buddy is looking into a first boat and I have been passing all the info that I have learned from you guys onto him. The wealth of knowledge on this forum is outstanding.
Author:  LouC [ Fri Oct 04, 2013 5:46 pm ]
Post subject:  Re: Vibration at low speeds
Well until you take it apart you don't know what you're going to need. That vib could be 100% from the props or not. If the bellows was new in 2009, and there are no cracks in the folds/rubber and not water inside you probably don't need to replace it yet. If you see cracks or any water then for sure change it. For the gimble turn it with your fingers and feel for roughness, if its smooth then I'd leave it be. Check the ujoints for play and see if you notice any rust coming out of the spiders themselves, that is a sign of wear in the rollers or cups. If you do change the bellows I'd use OE for that. Get a really bright LED flashlight and look in side for rust around the gimble if you see water in the bellows. The other thing to look for is rust on the driveshaft where it goes into the seal in the upper gear unit. If you see rust there and gear oil leaking then you have to take the drive to a shop to get that seal replaced and the shaft inspected.
The more regularly you do these checks, the less likely that you will have to make expensive repairs. I have not had to bring my boat in for drive work since 2005, but thats because the maintenance has been done every year. And also a bit of luck too (no bellows leak and its been on there since then, probably going to put on a new one this spring).

This type of drive work is not something you should fear because it is basically simple. The 3 scenarios that can make it a pain in the back literally are:
1) it was never removed and now its corroded in place
2) you don't have a drive stand and you can't get the drive, pivot housing and shaft to line up right. Get a stand like the one from Stumpys Fab works, if you plan on doing this every year. You will save your back and don't have to keep the kids in the house while you're working for fear of the combinations of cuss words that might come out of your mouth while fighting with this.
3) the bellows leaked and the drive was not removed for a few years and now you have a rusted mess in there, and the driveshaft can rust into the coupler splines.

Also get an alignment bar and check that alignment when you have the drive off.
Even tho Volvo does not say to, I'd coat the mating surfaces of the upper gear housing and the pivot housing (ie where the drive bolts to the transom mount) with OMC triple guard grease. Since Volvo does not use a gasket there, its possible for the drive to corrode onto the pivot housing (not common but it does happen even in fresh water). THAT, will ruin your day for sure.
Mine uses the gasket, I coat that gasket both sides with the magic OMC brown snot gasket sealer, including the studs, and my drive that sits in salt water 6 months slides right off, every time.....

If you could get it done fast enough,(before freezing weather) it might be smart to try it after the props are done, before taking it apart. Then if there's no vib, you know that was the true cause. You can still do the maintenance but just look for water, if so new bellows. If the vib is still there, then you have to check everything.
Author:  schoolsOut [ Sat Oct 05, 2013 12:07 pm ]
Post subject:  Re: Vibration at low speeds
Great info, Lou. Thanks! I am looking forward to my first drive removal this fall.

Here is a look at the prop overall.
Image

Here is the dinged blade.
Image

An un-dinged blade for comparison.
Image

I have the original aluminum prop that is basically in brand new condition. I put that on today and am going to see if there is a difference. I will take the boat out tomorrow and find out. When swapping out the prop, the nut that holds it on was finger loose. Is that normal? I would have thought it should be tightened down with a wrench.
Author:  Walt [ Sat Oct 05, 2013 12:57 pm ]
Post subject:  Re: Vibration at low speeds
Prop nut should be a Nyloc style nut (which should be replaced about every other season), and should be fairly tight... I use a 3/8" cordless impact, and then back it off just until it turns so I know it's not seized, if that helps. Should also be a lock washer that engages the prop hub, depending on style.
Author:  LouC [ Sat Oct 05, 2013 1:15 pm ]
Post subject:  Re: Vibration at low speeds
I never had a Volvo, my OMC has a big nut and a retainer that fits over the nut that a cotter pin is put through just like all the OMC outboards. I use a block of wood to keep the prop from turning the prop shaft and then tighten that nut pretty tight, then put on the retainer and the cotter pin. OMC triple guard grease on the prop shaft splines. I would think if its a similar set up the nut should not be loose.
this is what's on my OMC, does your SX have the same set up?

http://www.sportmann-marine.com/Prop-Nu ... 16745.html
this one is for OMC Cobras (86-93) only

http://www.sportmann-marine.com/Prop-Nu ... 16629.html
this one is for the SX, and joint venture Cobras (94-98)

I think the one that says OMC only fits the older Cobras like mine, I know when they went to the joint venture drives the # of splines changed so while the parts look the same they are not identical.
Author:  schoolsOut [ Sat Oct 05, 2013 2:48 pm ]
Post subject:  Re: Vibration at low speeds
http://www.sportmann-marine.com/Prop-Nu ... 16745.html
this one is for OMC Cobras (86-93) only

http://www.sportmann-marine.com/Prop-Nu ... 16629.html
this one is for the SX, and joint venture Cobras (94-98)

These look exactly like my setup. I will definitely tighten it down.
Image
Author:  Graham R [ Sat Oct 05, 2013 5:27 pm ]
Post subject:  Re: Vibration at low speeds
Lou,

Re the outdrive to pivot housing; VP recommend the use of their white sealing compound on the studs to prevent corrosion causing problems with taking them apart. I've used the one tube I bought in 2001 every year , still half left ! It seems to work well.

Graham
Author:  LouC [ Sat Oct 05, 2013 5:55 pm ]
Post subject:  Re: Vibration at low speeds
I'm sure that the use of any good marine grease + regular removal will prevent that problem.
Author:  230 Mike [ Sat Oct 05, 2013 8:58 pm ]
Post subject:  Re: Vibration at low speeds
I'll go against the grain and say a little vibration while turning at low speed is normal in boats this size. How much is too much, I'm not sure how to say.

Your u-joints are maintenance-free (which just means you can't grease them and WHEN they fail you'll have to replace them). Drive should still be pulled annually for all the other reasons though.
Author:  Graham R [ Sun Oct 06, 2013 3:07 am ]
Post subject:  Re: Vibration at low speeds
230 Mike wrote:
I'll go against the grain and say a little vibration while turning at low speed is normal in boats this size. How much is too much, I'm not sure how to say.

Your u-joints are maintenance-free (which just means you can't grease them and WHEN they fail you'll have to replace them). Drive should still be pulled annually for all the other reasons though.


It's rarely mentioned, but extreme steering at speed will cause the same sort of cumulative damage to the UJs that raising the drive excessively at speed will cause. In both cases, the UJs will be working at extreme angles..........................

..........and, as Mike wrote, WHEN they fail they need to be replaced. However, in the case of the maintenance free ones, the whole driveshaft needs to be replaced, meaning partial dismantling/ reshimming of the outdrive. "A nice little earner" for VP, their dealers and Rockwell, who make that assembly !
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