Vibration from Outdrive?
 

Hi guys, I have a little problem I was hoping someone might be able to solve for me.
I took my lovely better half on a leisurely cruise up a river the other day. We drove over a "muddy sand bank". The boat didnt actually stop it just slowed down a bit - we were only doing 5 knots!! - We didnt hit anything hard at all, we just slowed down.
We checked the river and couldnt see the depth as the water was a bit murky, so we went a little further up, and it happened again, so we turned around and slowly headed back out to the river mouth and into the estuary.
Once we were at the open water speed area we sped up to about 40kts.
We noticed that the boat was vibrating a bit and then
about 3 - 4 minutes later the overheating alarm went off. We of course stopped immediately and checked everything.
The temp gauge was showing 80+ degs, we called the service manager where
we get the boat serviced and he said we may have picked up some mud into the water pump and it wasnt getting enough water through to the motor to sufficiently cool it down at the speed we were doing.
So we headed back to the launching ramp at a pathetic 5 kts for about 1 hour.
The temp gauge never went over 75 degs, but we did noticed a sort of grinding noise and vibration that wasnt there before we headed out on our day trip.
We took the boat into the workshop on the way home for them to check over and repair - 1 week and $1590 later they reckon they had fixed it. The impeller was a "little bit" worn - I couldn't bloody see where it was worn, so that was replaced, the manifold heads were taken off and the water system completely cleaned of "burnt on" mud.
They took it out for 2 test runs and even though being told of the vibration problem, they gave it back to me saying it was running well.
We took it for a run a few days later, the motor was running well no problems there but the grinding noise and the vibration was still there.
It seems to vary in degrees as to which position the leg is in. In the fully down postion it is a bit different to say 1/2 way up.
The grinding sort of noise is there as well which is worrying also. It wasnt there before we hit these little sand bars.
The boat still runs great so the motor is doing its thing, the prop looks good - I havent put on another one to see if that fixes things at all.
So if anyone can lend there expert hands to this I would be truly greatfull.
I intend to get the boat back to the repairer and have him look at whatever could
be causing this, so armed with a bit of info would be really helpful.
It is an Alpha one leg with a 4 blade stainless steel prop attached.
There is no noticably movement in the prop (apart from around and around :)).
And for this sort of money, I want the bloody thing running perfectly.

Do you get the vibration when going straight, or when steering? I had the vibration only when steering, but it was really noticeable and bad towards the end of the season, it turns out my gimbal bearing went bad, and i needed to have it replaced. You might ask them to check yours. I'd try a different prop too, just to be on the safe side. Is there a prop shop around you could send yours to for repair and balancing? I'd also try and get the service manager from your service place to ride with you once so he can experience it. Usually that works to kind of "light a fire under them" to get the problem fixed correctly. believe me, i own a ford, so i know the value of a service manager. :)

Let us know what happens!

Hi Shabah, To tell you the truth I am unsure if it is worse when I turn or going straight, I never really noticed.
The Gimbal bearing was my thought too. I cant go out with the manager until I come off the rig which is unfortunately 3 weeks away.
I will try and get my wife to go out with them to light that fire as you say.
Do you know how much your gimbal replacement cost you?
Could this have been caused by the outdrive going through that mud bank?
THanks for your response.
Tony

I have spoken to the guys at sterndrive tech support, they seem to think it could be the prop is slightly out of balance or the shaft could be slightly bent.
They are a little unsure about the grinding noise so hopefully the shop will take the bellows off and check it all out. The boat goes into the shop on Tuesday 4th Dec so hopefully they will finally fix it.
I saw in another thread about the rubber plugs in the front of the prop, I will take mine out this summer and let you know how it goes.
BY THE WAY.........
Do all of you get the ugly black stuff (from the exhaust) on the stern of your boats?
Its a pain to get off some time and look ugly, is there no way of stopping this?
I will take a photo and show you next time I take her for a blat.

Ok, the mechanic took the prop off and checked it all out, couldnt find anything out of the ordinary, lubricated everything and put it all back together.
Thier senior mechanic (with 30 years boating experience) took it for a spin with another guy who has 10 years boating experience.
They both said the boat was running fantastic and was actually one of the nicest riding boats they have driven for ages (whoo hooo).
They could not detect any vibration at any speed and no grinding noise.
My wife and I took it out a couple of days after we picked it up from the dealer and also could not detect any noise or vibration.
Perhaps with the prop being taken off and everything being lubricated it may have fixed what ever it was!
By the way, they didnt charge me a cent.
I did notice when we put fuel in her on our trip out it WAS kind of empty though, so perhaps those two took it for an EXTENDED sea trial as compensation for charging me.:rolleyes:

Dudders,

Your shop should have pulled your drive. If the noise returns, make sure they grease the gimbal bearing (with non-teflon grease), check u-joints, grease the engine coupler, and check engine alignment. Those are about the only things that can cause a vibration/grinding noise when the sterndrive position changes.

I imagine they did pull the drive and upon re-installation greased everything up. That is why the noise/vibration is gone now. Also, just so you know Alpha drives have been known to whine a little. I know mine does but have been told it is completely normal by several reputable people (I live in Stillwater, OK where the Mercruiser is located:wink_thumbup:
Hope this helps,

~J

jmills is right..the R&R of the drive and the greasing up of everything may have been all that was needed but you will just have to monitor things for a while.

The end result was good news though! It saved ya a few $$$$

ps...tell me again what it's like to be in the middle of summer right now...... :(

Been there, done that... :yes_grin:

I used to work at a high performance marine shop. Most of our customers didn't notice or didn't care. Probably b/c most of them burn more gas in a weekend than the average boater burns in a season...

Are you hatin' on this brisk weather we've been having? I took the dog for a walk at 8pm last night, and just about froze my proverbials off...

I am hatin' it! I came out of a hockey arena here last night around 9pm and i think my 'proverbials' crawled up inside where it was still somewhat warm. ;)
The first place i headed was a nearby Timmy's to get something hot to drink...

That's kinda funny... Ron Joyce's boat: "Timblitz" was one of those "customers" I was referring to in my previous post. IIRC it was a 42' Scarab with dual big blocks. Wheeeee!