Causes for gears to break?

[loco boater]

I purchased a 2000 SeaRay with a 5.0 Mercruiser and a Alpha 1 gen 2 outdrive with 387 hours on it.. Being new to i/o i have many questions so here goes. First thing right off the bat I broke the scag off. A new one was welded on with the out drive left on the boat. Once I reached 400 hours I took it in for service on both motor and outdrive. There were a few things brought to my attention, bad o rings on the drain plug and some water in the drive, noisy gimble bearing, leaky bellows. Gear lube, gimble bearing, bell housing, shift cable, and bellows were all replaced. took it on a sea trial and all was well. The next time we went out the gears in the upper unit, after the u joint sheared off three teeth. what would or could cause this? 4000rpm

 

[Bondo]

Re: Causes for gears to break?

The next time we went out the gears in the upper unit, after the u joint sheared off three teeth. what would or could cause this?

Ayuh,... They were Probably Cracked when you struck bottom, or some other time during the last 400hrs...

 

[JustJason]

Re: Causes for gears to break?

some water in the drive

There you go right there... thats your answer. Water is a very poor lubricant.
Low/no oil is the #1 reason for gear failure.

 

[loco boater]

Re: Causes for gears to break?

Thanks for the prompt reply. Follow up if I may, it has a resivoir and is full does that insure the drive is?

 

[jaxnjil]

Re: Causes for gears to break?

no; if your getting water intrusion it will fill from the water leak and go up.
need to watch level in bottle hot and cold and make sure it dosnt go up or down. up; water coming in and trapped-going down= leak and loosing oil.

 

[bigskiohio]

Re: Causes for gears to break?

drain some oil before you go out if water is there you will see it before you go out.

 

[Knightgang]

Re: Causes for gears to break?

I agree that the splines probably cracked when you hit bottom, it just was not discovered on the first repair. However, three primary things will cause gears to break. Binding, heat and lack of lubrication. Water is heavier than oil, so if it is getting water in it, it will displace the oil and not lubricate properly...