2004 Yamaha 60 HP 4 stroke

blackdogpile

Cadet
Joined
Feb 21, 2010
Messages
21
I had my boat out this past week, it ran great for 7 days straight. Today I was going about 20 mph when it pretty much stopped. The motor runs fine but question splines or gears in lower unit. Boat will move at low rpm's, but when I accelerate engine just revs and no movement of boat, and a whine from lower unit. I had to make it about 1 mile to boat ramp just idling. Help
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: 2004 Yamaha 60 HP 4 stroke

You probably have what is called a "spun hub". If you remove the prop and look closely at the rear of the prop you will see that the hub has a rubber spacer between it and the outer, blade area of the prop. What happens is the bond between the rubber, the hub and the blade area lets go and begins to slip at higher power settings. It may hold at very slow speeds but when you try to go faster it cannot hold any longer and the hub spins. To verify this, make a mark on the hub and in line with that one, make another mark on the blade area. Now run the boat until it begins to act up. Now check to see if the two marks are still in line. If not, the hub is spun. If they are in line, then something else is going on but the spun hub is very likely the issue. The prop can be rehubbed by a prop repair shop.
 

blackdogpile

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Joined
Feb 21, 2010
Messages
21
Re: 2004 Yamaha 60 HP 4 stroke

Can you check it out of the water? Can you put it in gear at full throttle, after making the marks on hub and prop, and spin it by hand?
 

mommicked

Lieutenant Commander
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Dec 15, 2009
Messages
1,700
Re: 2004 Yamaha 60 HP 4 stroke

You may see the damage if you remove the prop and look at the hub carefully.
 

4x4xEric

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Joined
Mar 21, 2011
Messages
12
Re: 2004 Yamaha 60 HP 4 stroke

+1 silvertip
You could try it in a barrel of water, but it really needs the pressure of pushing the boat to make it slip.
You could leave it on the trailer and just put the motor in the water on a steep ramp.(just check the prop is clear before you start the engine)
Definitely sounds like a spun hub to me, has the prop been weed fouled or hit sand, these are conditions that can cause a spun hub, due to extra pressure on the bonding surfaces.
good luck and I hope it is a spun hub as this is the cheapest option to fix.
 
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