Speratic Ceasing Noise

[FourSqChamp]

I recently purchased a 1999 Moomba Kanga that had only 27hrs on it when purchased (basically brand new). I have put about 23 hours on it in the last month or so and last weekend I took it out as usual. Everything was fine until while under power and on plane I started hearing a sporadic noise that sounded like a blower seizing up. The noise isn't coming from the engine, it sounds like its coming from underneath the boat. I checked the prop and its on tight, there are no weeds sucked up into the intake and we drained and refilled the drain plug. We also checked the pressure in the system to see if maybe the pressure was dropping and the clutch was slipping but the hydraulic pressure was fine. If anyone has any other ideas on what might be causing this please let me know. Thanks!!!

[Catdog1]

Not sure. Need to give some more data about the situation, rpm, etc.

One unnerving noise involves the shaft spinning in the cutlass bearing, a rubber lined brass bushing essentially, located in the shaft support strut under the boat. On the trailer, turn the prop by hand and see if you get a noise and if so whether it bears any resemblence to what you hear under power.

[moombakanga]

I've got the same boat with 75 hours on it and it sounds like were both having the same noise occur. Its sounds like a high pitch squealing noise. Almost like a belt slipping but worse. The first time it occurred I couldn’t pinpoint where the noise was coming from. It sounded like it was coming from the front of the engine so I replaced the impeller on the raw water pump. Next trip, same noise. It seems like the noise will not occur if I'm running along at lower speeds. Once I plane out like to travel to a different part of the lake and run for a while, the noise will start. Once it starts, you can see the vent cap on the transmission vibrating and the noise seems to be coming from the transmission area. There seems to be no slipping of the transmission when this occurs. Transmission fluid level and temp all look good. The vibration that accompanies the noise is not that bad. If it were not for the noise, the vibration is so minimal that I wouldn’t even give it any consideration. When running the boat planed out and the noise starts, if I throttle way down the noise stops. If I throttle back slightly the noise continues just to a lesser extent. If I slow down and let the noise stop and then get right back on plane, the noise will return. It seems like if I slow down and wait for a while, the noise takes a while to return once I get back on plane. I thought maybe it was cavitation but it seems like the noise would go right away once I dropped the engine speed some if this were the case. I have looked close at the shaft. To the naked eye it looks good and straight. The rudder ??? that the shaft goes through and it holds the shaft at the bottom of the boat looks straight and no apparent signs of hitting anything. The rudder is solid and wont move if you put pressure on it. The bushing that supports the shaft through the rudder (cutlass) shows no slack side to side or up and down. Again the boat has very low hours for its age but that really means nothing.... The prop is dinged up some and one blade looks a little bent at the end. This is on my to fix list. I dont know if the prop would set up this noise or not.. I decided to try to get the sound to re-occur while on the trailer. Realizing that there would be no load on the shaft, transmission as you would normally see while on the water, I wanted to try anyways. I set up the water to the engine, water hose to run on the rudder to keep the Cutalss (?) bushing / bearing cool, one hose to spray on the shaft nut / packing from the bottom of the boat. Lastly one more hose to run on the shaft nut packing from inside the boat... Cranked the boat up and ran it at higher RPM's for more than 1/2 hour and just as I figured it was flawless ...no noise. I'm not sure who to try to call for advice. I’m down on the Gulf Coast in Texas and its hours to the closest service. I’m sure this kind of diagnosis can get pretty pricey. I'm hoping maybe you have resolved your issue? If anyone has any suggestions please reply... Thanks, Cliff

[musgrove]

Tomorrow, Halloween 05, we will be looking seriously at a Moomba Kanga about 100 miles from home and these reports give us a few concerns. It has 150 hours on the boat, so may have resolved it if/when it happened. Your notes will be given to the seller to get a reaction. We do NOT have to buy the boat, but felt, after a lot of searching, this may be our best opportunity and best time and best price... But...

If anyone is still up and can add to this, it would be appreciated. Thanks, John

[email protected]

[smokedog2]

Musgrove,

Test drive an hour. Stop, start, drift, check for leaks & noise. I would not buy a used boat without an engine inspection by your dealer or theirs.

Check the shaft, run everything with a switch several times.

Get the Mx history from them, then call the dealer and ask for the Mx history (stop by if you can, stop by with a note signed by the owner saying the dealer may release all the mx info they have on boat xyz). What has been done, what were the recorded hours etc. You may be surprised to learn that some people will go to the trouble of disconnecting the hour meter. I put 92 hours on last year. 150 hours is nothing.

Some people are competent mechanics and no oil change history is understandable. You have to decide if it is believable.

I bought new, buying used makes me nervous but a couple guys with funny noises should not distract you from the more important issues related to the boat you are looking at.

If the boat has a good pedigree (owner history), buy it and post a picture.

SD2

Oh, if you are NOT going to HAVE to buy the boat, do NOT bring the kids.