volvo penta MD11c - raw water pump leak causing corrosion

[SAWDOC]

My ancient MD11c was professionally overhauled in year 2000 and has operated well in my short ownership. However after lift out earlier this month I noticed some corrosion on the engine block and on the metal sail drive sealing ring resulting I think from water weeping from the raw water pump casing (not from the intake pipe). Is this a common problem and how is it fixed?

Thanks

 

[aquaplane]

There are a couple of seals on the shaft that wear grooves in the shaft and cause leaks.
The one nearest the pump lets water out and it should escape through a hole in the casing between the two seals, hopefully the one nearest the engine is man enough to stop the water getting into the engine sump.

I replaced the pump on mine but it is possible to overhaul them. Usually a new shaft is needed as well as the two seals, and an impeller too.

 

[SAWDOC]

thanks bob
If i withdraw the impeller and shaft, should any grooves be apparent?

 

[VicS]

thanks bob
If i withdraw the impeller and shaft, should any grooves be apparent?

Ideally there should be no grooves. Overtime the seals will wear groves in the shaft. No problem all the while new seals will take up the wear but eventually if the shaft becomes too worn to make a watertight or oiltight seal the shaft will have to be replaced or sleeved.

There is a workshop manual on http://www.bluemoment.com/downloads.html which may be useful if you do not have one.