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thriller
07-05-2004, 12:38 AM
With nearly 60 hours on engine/drive now, I have noticed a vibration that seems to come and go..I thought originally it was the props..Then once I timed them and had the props cleaned up it seemed to be a bit better. Suspicious, I removed the drive and checked the u joints/gimble/and alignment. All seems to factory tolerances. Changed gear oil and checked magnet for filings. All seems clean and no concern for alarm. It seems to be only under load ..Any idea's? Seems while under way I can make it better by trimming the drive up until I find the quietest setting..Still noticeable though. You feel it in the seat??Then when I pulled my 4 year old on a tube at like 5 mph it was really loud..Is this normal?Any input greatly appreciated..
Mike:banghead:

Bad-Tat
07-05-2004, 07:15 AM
Mike,
Mine does the same thing when the props are all the way in the water. Varies depending on rpm and load and doesn't go away until you get the props ventilated and half out of the water. Just another Blackhawk difference.

MOP
07-05-2004, 07:32 AM
I think it is the design of the props, I did a lot of hunting around on surface piercing when I was going to do the A drive, in the article on the site below is a section on cavitation that is quite interesting. The whole thing is good reading for those running surface piercing wheels, the writer I think this is the fellow that CDMA knows and had spoken of.

Phil

http://www.simplicity-marine.com/surfprop.htm

GeneD
07-18-2004, 09:33 AM
Check your engine alignment.