Lower Unit Lube Change 1969 Mercury 7.5

[tmorin]

I must be missing something, this motor apperars to only have one screw to drain/fill the lower unit?

I want to change the impeller, do I really need to flip th emotor on its head or can I get away with tilting it or laying it down?

Thanks

 

[tmorin]

Found the drain, any advice on the impeller replacement?

 

[tpenfield]

Check the oil seal that is just below the impeller for any signs of oil seeping through. Also take a look at the drive shaft in that general area for signs of pits in the metal. Mercury did not go with stainless steel drive shafts until about 1978 on those motors, and the regular steel shafts would tend to deteriorate, particularly in salt water.

Getting the key to go back in between the impeller and the drive shaft is a bit tricky, but be patient with it. Give the impeller housing internal surfaces a wipe of liquid soap to provide some initial lubrication.

Also, the lower unit sometimes is a bit stubborn going back on. Don't force it, just wiggle it enough so that it slides in. Make sure the water tube leading from the impeller housing mates with the tube leading up to the engine.

 

[tmorin]

I can't locate the tell tale? there is a flush plug that drips but where is the majority of the coolant exiting?

 

[tpenfield]

The telltale is right next to the flush plug . . . so that is probably what is dripping. Much of the water goes out through the exhaust. I had to bore the telltale hole out about 1/16" larger than it was so that it would not continually get clogged.

You will probably need some wire (or similar) to clear the telltale hole.