Pressure testing lower unit to locate the leak. 1991 150 TSLEIE

[w2much]

I apparently got it wrong. I resealed my lower unit and it is still leaking. Disappointing at least. Anyhow I have a pressure tester hooked to it while the lu is still attached to the motor and it is underwater. Bubbles are coming from the top hole of the four water intake hole which are on each side. The prop shaft, no bubbles at all. If it were the shift rod seals I think the bubbles would travel straight up. Lower unit has to come off either way. Can it be taken for granted that the leak is in the driveshaft seals under the water pump? Just want to order parts ASAP for when I get to the fix. I realize I can again test the lu once off the motor but would like to have the parts ready for when I can get it all done in one session.By the way the pressure tester is hooked up to the oil vent, not the fill if that matters.

 

[oldboat1]

Think you might pull off the l.u., and test it submerged in a tub. Should be able to see where the bubbles are coming from that way. Beware of too much pressure -- 6 or 8 lbs. would be good.

 

[boobie]

You can put up to 14 psi in the LU on the pressure test.

 

[Chris1956]

Gee, soapy water locates leaks as well as a tub. Pull the gearcase and use some to see exactly where the leak is. It could be driveshaft or shiftshaft seals or cover gaskets.

 

[oldboat1]

good point. Cleans up some exhaust crap too.

 

[w2much]

Ok, so here we are. Pulled the lower and located my leak. Coming from the drive shaft seals, which are new. Of course installed with out the special tool . When I pulled out the bearing housing I could see the spring on the lower seal had become unseated. I put the spring back in place and the bolted bearing housing back in place, this time with a home made bearing protecter. It will hold pressure although I do not really trust that my compression tester gauge is a good gauge to use.
My question here is now regarding the wiggle room of the driveshaft in the bearing housing and thus the seals. If I wiggle the drives shaft there is enough play to make the seals leak at the shaft. Bearings look good, Just curious if with the two part driveshaft there is that much more play than with a one piece.Once in place and into the power head does the play go away? Or might the bearings be worn that much that I need a new housing.?

 

[Chris1956]

The joint in the two piece driveshaft is just above the bearing and seal. When the bearing carrier is off, you should see the joint. You should also be able to see the play in the lower driveshaft-to-bearing, when the seal is off.

The crowleymarine site will show a diagram for your gearcase, so you can see if you have the 2 piece driveshaft. If you have any play in the lower driveshaft to bearing, it should be replaced.

 

[racerone]

Those 2 piece driveshaft lower units will show a scary amount of wobble.-------Pressure test with the driveshaft vertical, or with lower unit installed on the motor.

 

[w2much]

I will check the lower drive shaft, it is a two piece shaft.. I also read some older post on the play and yes it is normal. I had the lower unit installed, that is when I first noticed a leak. Regarding the play. Racerone is on track with me as Vertical and installed are both mentioned. If I wiggle and or turn the driveshaft while the lower is not installed I can make a good seal or a leak by turning the driveshaft or wiggling it. So therefore I am thinking what assurance do I have that once the lower unit is installed it will be in proper position to be water tight and sealed?

 

[racerone]

?----Pressure test it once bolted to the exhaust housing.

 

[rothfm]

Any updates on this post? Have a similar issue and was curious if you reinstalled the LU and tested it once vertical and locked into the crank?

 

[w2much]

It was not vertical nor installed at the time of the test.I knew it was leaking so I took it off figuring it had to come off anyway.. I read the directions ect. They are good . Still had the leak. What I found was the the driveshaft had tiny rust pits which were allowing water in, air out ect. I fine sanded the shaft where the seals were supposed to seal and now all is good. I have retested before install and no leaks. No air in no air out,. Good to go. It is not always whatcha think, Sometimes its what you don't think.