mysterious outdrive oil leak

[bradeyj]

1997 mercruiser 5.7 with MR drive. I replaced 70's era 351 Ford Winsor with chevy 350 and outdrive was on in storage for about 6 months. Did not have a problem with it leaking when it was on the boat with the Ford engine. Here is my question. I thought for sure it was leaking out the propeller shaft seal behind propeller but after removing it I had no evidence of where it is comming out from. No evidence of a leak between upper and lower unit seal and the only place I see oil is from oround center part of propeller and down the skeg on to the concrete below. outdrive is in down position and has been for a while while I was timming and tuning new engine. Can anyone narrow it down to which seal this is? Thanks for your help in advance--bradeyj

 

[Bondo]

Re: mysterious outdrive oil leak

Ayuh,.... Welcome Aboard,......

A Pressure Test will tell you Exactly where is leaking,.....
Drain the oil, pressurize(10/ 15psi is Plenty) the case,+ spray some soapy water around,...
You'll See the Leak....

 

[Don S]

Re: mysterious outdrive oil leak

Have you removed the outdrive from the boat yet? IF not, do so, and look for water in the bellows.

 

[bradeyj]

Re: mysterious outdrive oil leak

Thankyou will do pressure test after I get the lower unit back on. decided to remove it to get a closer look and I planned on replacing the whole water pump/impeller assy while I was at it. Water pump and impeller did not look too bad, but seals looked to be a little worn. Shaft seal surfaces looked good with no ridges or pits. Springs on the insides of some of the seals were rusty but intact. Also removed seal on reverse/shift shaft this seal was missing most of the spring and the remainder was rusted and fell apart when removing. Looked like the oil was comming from this area around water pump and draining down through exhast passage and onto prop and skeg. I am going to take another look tonight when I get home from work up through the upper gear box and exhaust to see if there is any evidence of oil in the exhaust cavity. If so then I will look in the bellows. Thanks---bradeyj

 

[bradeyj]

Re: mysterious outdrive oil leak

Will check the bellows just to make sure I don't ruin anything ---Thanks bradeyj

 

[bradeyj]

Re: mysterious outdrive oil leak

ok I went ahead and removed and replaced outdrive water pump and shift rod seal. I did not see any evidence of oil leak/residue in the upper drive void. It looked like all oil was comming out around water pump area as well as around shift rod location. I re-assembled today and ran engine for about 10 minutes and did not notice any oil seeping out of the prop area as before. I will re-post if I find any more leak in the future, thanks again for all your help---bradeyj