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Lower unit question

K

kboomisme

Contributing Member
I just bought a 79 Evinrude 85 hp for $50.00. I have no history at all on the motor. The man I bought it from said it was his dads and he passed away so he knew nothing about the motor. I put it on a stand and started to check it out. It seems real clean. I took off the air cleaner and all is clean. No mice nests.... It has fire to all 4 plugs. It has great compression in all 4 cylinders. I live in Maine so there is no way to start it in a barrel so this is my question. Is there any way to tell if a lower unit is good or bad without running the motor? I took off the lower unit to replace the water impellor. The shaft doesn't have any play. I hate to put to much into the motor if it has a bad lower unit. If I turn the shaft by hand in forward and reverse, the prop turns. Sorry this is so long but I want to give as much info as I could. Thanks in advance.
 
The same lower unit is used on the 140 hp model.----If oil is clean the unit is likely in good shape.----One thing I usually do is to remove the bearing housing below the waterpump.-----Then inspect the thrust bearing in there.
 
Ok, I just drained the oil. Looks very clean. There was some very very small pieces of a brass colored looking stuff but that's all. There was no water or milky colored stuff in there, The motor was on an old boat outside over the winter for a couple years as well. I pulled the four bolts out under the water impellor and pulled that cover off. There is a bearing in that cap and also a weird flat looking bearing in there as well. Thay all seem to be good but not really sure how to tell if they are good or bad. Thanks for the help.
 
Ok, I just drained the oil. Looks very clean. There was some very very small pieces of a brass colored looking stuff but that's all. There was no water or milky colored stuff in there, The motor was on an old boat outside over the winter for a couple years as well. I pulled the four bolts out under the water impellor and pulled that cover off. There is a bearing in that cap and also a weird flat looking bearing in there as well. Thay all seem to be good but not really sure how to tell if they are good or bad. Thanks for the help.
 
The bearing housing is sealed with an o-ring in the upper groove.----Inspect and replace that if needed.-----A light smear of sealant is optional.
 
If you are looking at the seals you will not see the o-ring.----Look on the other side as it has to be there in the upper groove.------Just installed new o-rings on 3 gearcases that I have done.
 
I found it. I cleaned it all up. I put a small amount of silicone on that area and bolted it all back together. How does that all get lubricated? From the gear oil in he bottom?
 
(You can also pull it into a vacuum also and recommended for back to back seals)??? Sorry, I am not su what this means. I understand the pressure part though.
 
Is that with the bearing housing installed ?-----------1/4 is quite a bit, so do you have an exact measurement instead of " about 1/4" or so "
 
O.k. guys. I did a vacuum test last night. I have the impellor off and when I pull a vacuum, it is sucking air in around the drive shaft seal. Is that normal and the impellor housing seal stops that or do I have to replace that seal? I looked it up online and it says you have to buy the whole bearing cap, bearing, and seal all in one.
 
I did a presure test and it is leaking around the shift shaft. I pulled the cover off and there is no seal on it. How does it seal up? Is that rubber dust cover on top suppose to seal it?
 
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