Hurth 630 output shaft leak

[jl_photo]

I am trying to get my dads boat operational, he has a terminal cancer and I want him to enjoy his last season of boating. Immediately after having the boat serviced in dry dock, the transmission developed a strange leak. The prop shafts were removed but no work was done on the transmissions. The lip seal has a tiny bit of ATF on it but no drips. The oil is leaking out the 2 unused set screw holes in the prop shaft coupler.

Hurth 630 transmission with a leak.

The leak seems to be from inside the output shaft coupling. Mu understanding is that the output shaft seal runs on the O.D. of the coupling and that there is an O ring on the output shaft inside the coupling.


Does anyone have a photo of the output shaft disassembled?

How much force is necessary to remove the output shaft coupling?

I am doing this in the water. How far back do I need to move the Prop shaft to remove the coupling.

The O ring is on backorder from Hurth. Can I use a standard round o ring that is rated for ATF or is it a special O ring.

Thanks so much

John

 

[Don S]

Re: Hurth 630 output shaft leak

What is the Mercruiser SN of the engine. The procedures are in the engines serial number, but have no idea which manual at this point.

 

[jl_photo]

Re: Hurth 630 output shaft leak

What is the Mercruiser SN of the engine. The procedures are in the engines serial number, but have no idea which manual at this point.

I do not have the serial number handy.

All 630 transmissions are the same in this regard according to my source. No service manual would ever describe this repair operation outside of a dry dock.

I will probably need to fabricate a low profile puller to remove the coupler unless it just slides off. I may also need to remove the prop shaft coupler to have enough room to slide the transmission coupled off.


The repair manual will also not describe the o ring. It will just list a part number.

 

[jl_photo]

Re: Hurth 630 output shaft leak

I spoke with a very helpful gentleman at:

Simplicity Marine Products, Inc
635 43rd St, Blvd. West
Palmetto, FL 34221 USA
Phone: (941) 722-8475
Fax: (727) 499-7457

Simplicity Marine Drives - Home Page

He explained that this leak is almost always caused by the output shaft flange bolt being loose. It was. I tightened it and the leak stopped.

We had the peerless bearings in the struts replaced in Seabrook at what seemed to be a reputable boat yard. It seems that most of the boat mechanics in our area are either unskilled or winos. In addition to loosening this bolt that was lock-tighted on for no reason, they also ran the engine dry and melted the sea water pump. The boat had more problems after they worked on it than when it went in.

The easy way to bring the flanges back together is with a pair of threaded rods with nuts. Glad I had them in the truck.