View Full Version : Mercruiser 470 sterndrive problems

08-29-2006, 09:25 AM
"New boat (to me). I am new to I/Os. I have about 5 minutes on it since I've owned it. I bought it on Saturday and the manual I ordered hasn't come in yet, so I'm flying blind here. About 2 miles out there was a skipping/stripping type noise as I was throttling back, then all forward motion ceased. It is a 1979 Sea Ray.
Now when I try to start the motor it either dies instantly when I try to go into gear or revs like the cold start button has been pressed and there seems to be no attempt to engage the drive.
There is no noise from the drive at all.
On the trailer, motor off, the prop spins freely in neutral, and I cannot turn it by hand in either forward or reverse gears.
Possibly a problem with the ignition interrupter switch or throttle control?
One thing that I thought about later was trying to start it in gear, but with paddling to shore and staying out of barges' way and then trying to figure how to get back downriver to the ramp, I forgot.
Any and all suggestions or pointers would be appreciated.
[email protected] ("")"

08-29-2006, 07:12 PM
"Busy afternoon. I pulled the unit. It looks like I have stripped the upper AND lower R&P in the drive.
Great. How can I identify the drive and ratio so that I can try to find another unit or parts for this one?
There are no numbers, and the decal is obscured. I was told that it was a 2:1 ratio unit, not original to the boat. I think that it is a type 1, pre alpha unit, but I am not sure. How can I tell? It has a lifting eye in the top cover. Have also read that is compatible with alpha 1 drives.
Is this so? Does this apply to internal parts exchange or just that one unit will replace the other?
This boat is done for this year, (2 miles!!) but I want to get it repaired soon so that I can have the garage space this winter.
Any help or suggestions appreciated.
[email protected] ("")"