Vibration turning to right when pulling

[bergermaister]

I've got an '01 Mobius V and have a weird vibration when turning to the right at speed and under a load, either with ballast filled making a turnaround or pulling a few kids on a (dreadful) tube. It almost feels like the transmission wants to slip, like it starts to give, but it never actually does.

Last summer the local deal went through it from bow to stern and didn't find anything wrong. This year I've found the same vibration/whirring sound when turning to the right, again only at speed with a load. A friend was telling me this is probably prop wash but I'm having a hard time believing that. The boat only has 200 hours, is always serviced and is in immaculate condition.

Anyone have any ideas what might be causing me the problems? Other than the right turn vibration thing it runs perfect straight line and left turns are nothing.

[JoeTechie]

The fact is only happens when turning right leads me to agree that it is cavitation or ventilation since that is the direction of force by the rotating prop. Both create a "shudder" as the prop over-revs and has periods of low and high force as the blades go through air-water-air-water....

You are probably turning too tightly. With a load of ballast, you should be turning wider since the hull is not riding as normally designed and more of it is out of the water. There were 2 threads about this a while back.

-Joe

[bergermaister]

Thanks - I did a search on the forums but didn't find any threads and I just joined today!

That's a relief to hear that is "most likely" the cause. My buddy also mentioned there is a certain brand of prop (Acme I think he said) that would help to eliminate this. Sound familiar at all?

[JoeTechie]

I've never heard that Acme is any better than OJ, or visa versa. Interesting thought though - they are shaped differently.

-Joe

[smokedog2]

It was probably a soggy chicken.

SD2




God I need to get to the lake.

[gotmyboat]

Hey Berg -

I have the same issue when doing the 'spiral of death' to the tubers. It is just cavitation. It is a little un-nerving the first couple of times it happens. There is nothing worse than breaking your boat pulling tubers!! That happened to my buddy Mem. Day weekend. While pulling a tube with his '04 Tige 21i, one of his swim platform mounts broke. The heavy teak platform started to swing out and destroyed his TAPS system. The boat is now in the shop for $1-2K in repairs. While it is in the shop they will also fix his bad starter, dead speedo, and transmission shudder. I told him to buy a new Moomba instead of the used (rental) Tige. We both bought them before last summer, and I have 80 trouble-free hours on my Outback. He has to hit his starter with a hammer to make it work. Who got the better deal?

Enjoy your boat, and be safe,

Dave

[bergermaister]

Thanks Dave-

I have wondered if I'm actually sliding a little too much in the turns creating the white wash and if a fin or skag on the bottom would make any difference. Not going to mess with it though - would rather spend my money on other goodies.

Funny you mentioned the problems with the Tige. I was looking pretty hard at those before coming across my boat. I'd be driving one now if the seller hadn't backed out on me last minute. Kind of glad he did since I found this MobiusV instead.

[smokedog2]

Put a few gal in the center bag - no more cavitation.

Not that I pull tubes or anything.

SD2

[jcmoomba]

I just purchased a 2000 Moomba Outback LS with 60 hours. Great boat but a little concerned about the "reving or slipping" while pulling towables. While in the figure 8 encounter a "rev" or feeling as though you
have a clutch engaged. The RPM gauge never moves...very strange.

Part II. Are you running Premium fuel? I fueled up with unleaded 89 octane and after a few minutes around the block the boat would not idle until I added a fuel additive.

Had no reservations about the boat (4th time on the lake) up until now, but kind of thinking twice about the Moomba. Can someone make relate?

Previous post about the reving sounds like my problem, but not sure.

Thanks!
Jeff

[Buttafewcoe]

These boats are highly manueverable, but basically designed to pull a skier or boarder in a straight line.
.
Question: On a sterndrive, does the prop sit lower in the water once the boat is on plane more so than these ski boats? The only time my old I/O aerated was in hard turns pulling a toober.
.
B