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1965 Evinrude Yachtwin 3hp possible bad lower unit

Perhaps put a grease fitting an a spare drainplug.----Use a grease gun to put some controlled pressure into this unit.-----You never know what will happen.------Seals might pop out. ----Bearing housing might pop out.-----You might crack the case..----The thing is no good until you do take it apart for inspection.-----Gears might be badly rusted.----Would I do this ?---Doubt it , since I just have to look in the parts bin for good used parts.
 
Great idea, Racer. Get some pressure on, then tap it. Gotta make me one of these. Just a 3/8" NC thread.
 
I'm in the middle of adding seals and o rings to my
78 6hp lower unit.
Found the individual parts on ebay, local etc.
Cost maybe under $30. Also I made my own
Seal removing tools years ago and they work
Pretty good.
Sometimes you have to Fab your own tools.
 
I made a spanner wrench for the big Mercs.....WAY better than the crap you can buy
.....may post a picture of it someday. Built my own air compressor in 1975.....when I was 18 and counting pennies....probably the best quality products, no longer available.......still running my shop today. Sure I have made stuff that breaks, you learn to do a better job next time. But what I've learned, when I myself build it, and it breaks......2 important things happen. What, you ask? First.....there is only one person to blame.....Second.....your gonna know how to fix it.
 
I'm going to see if I can get away with not doing the prop shaft seal. it appears to be sealing fine and the seal next to the impeller is the one that looked really bad. If the prop seal is bad oh well its easier to do it with the lower unit on any way!
 
Once I put the new seal in I'm going to run it in a bucket for a bit then check the oil. If it's milky I know what I need to do lol
 
Right, but might not show up right away in the "bucket". Make sure water level is well above the water pump. I get nervous when operators use the word "bucket". Somehow I feel safer when I hear "drum". LOL.
 
Colezay said:
Ok ive taken the lower unit mostly apart. I’ve gotten down to the gearcase head behind the propeller and it won’t come off! I don’t want to damage it in any way but the thing is stuck on there.
Click to expand...

If anyone has mentioned this already, I keep overlooking it. In my years at the work bench, whenever I come across any removable part frozen to its mating portion... a hand held Propane Torch with a blow torch tip, in your case, heating the outer surface of the housing surrounding that gearcase head will free it. Some method of securing that lower unit from moving, that torch, and water pump pliers out to do it!

If you've already got it off... keep this in mind for the next one. :cool:
 
It's still stuck on there, hoping that the propane torch won't damage the paint too much, not that it's in good condition right now... lol. I might be able to get away with not doing the prop shaft seal but I'm not entirely sure since I don't have a pressure tester.
 
If you have a small air compressor... using just a rag as a seal for the air pressure tip at the fill hole of the lower unit... if you're able to adjust the pressure between 7 to 12 psi, so much the better, that'll reveal a bubbling leak rather quickly.

Note that high air pressure could make a faulty seal slam shut.

Jamming the air tip against the rag won't keep pressure applied properly forever but it's worth a try. Works for me.
 
I’m going to try that this weekend with a buddy of mines air compressor, I need to have the drive shaft in to do the test, right?
 
Y'now what? I'll bet air pressure applied like that will blow that cap off without damage. Stand out of the way, though.
 
I am not sure, but i think it might be easy to find new used lower unit from some seller. I heard from the previous owner of my 3hp Lightwin, that he needed replace the original lower unit with used one, and he got good but used lower unit from the dealer who was selling and servicing used Evinrude / Johnson motors.
 
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