View Full Version : 99 Mobuis vibrations / leak / wondering steer

07-04-2008, 01:05 PM
So, I buy a used 99 mobius. The test drive was pretty good but it was cut short due to a thunderstorm. The guy made a great deal so I went with the buy without much more looking.

Just put the boat in for a second run today and noticed a few things.

1. Above 20 MPH there is a growl and slight vibration that comes in and out. Prop bearing maybe? Cost to fix?

2. There is a leak around the prop shaft. About as much volume as a super soaker water gun at low pressure. Prop shaft sael? Cost to fix?

3. The boat likes to wonder some, especially while going over waves. I can tell that the rudder is slightly loose, but not bad at all. My 88 Ski Centurion tracks very straight, but it is an outboard and didn't know if some wondering was normal in these inboards... Cost to fix rudder?


07-04-2008, 06:01 PM
One other question I forgot about... The boat also seems to shift quite a bit as the weight transfers from one side to the other. It's like an offshore boat but not as bad. The Vee is not so much that I would think that the boat should shift. Is this nomal?


07-04-2008, 11:17 PM
I have a '98 mobius, same deal when people move around and weight shifts to one side boat kinda "walks" on me. get balanced side to side and she'll drive like a car. Still definetly will be different from a outboard. little "looser" feeling. the water, leaking around rope seal may be a little much, the new packing seal is cheap, just dont know how handy you are...the vibration could be a bearing or bent shaft, possible drive link alignment, I'd begin by looking at prop, putting in gear on a fake lake & watch shaft for wobble., removing floor panels and look for "slop" in drive line. I bought my boat bout Christmas '06, with around 500 hrs. have about 800+ now and have thouroghly enjoyed. You'll find you can do alot of repairs / service yourself. keep us posted, bob

07-06-2008, 10:41 PM
bobwells: Is it ok to spin the prop out of water? Wont the shaft begin to overheat/cause damage as it spins without some sort of lubrication?

Reason I ask is that I wanted to do this one time and as soon as the prop started spinning ever so slightly, there was a nasty squeaking noise. Scared me a bit.

07-07-2008, 01:04 PM
Turning by hand won't be an issue. You could spray water hose on it some, but I think that is common as I had to replace a shaft last year and it made that noise while working with it.
big concern would be running motor out of water and putting in gear.. that would overheat the bearings without water to cool it..