does any one know how long a number 4 speedmaster will last on a pleasure boat , im wanting to put one on my mirage and run it up and down the river on the summer weekends ... i heard that they should be gone thru and looked at , every 5 hours , the gears would have to be replaced at 10 hrs, along with the drive shaft? . is the rebuild really $3000 with the cost of parts and labor every 10 hrs? i also heard that you should change the oil everytime out .........

any info would be great . im not gonna race it , but i will stretch it out a few times over 8000.