Home › Forum › Ask A Member › 1971 9.8HP Mercury 110 lower unit seized
- This topic has 7 replies, 5 voices, and was last updated 8 years, 8 months ago by
billw.
-
AuthorPosts
-
October 28, 2016 at 8:52 pm #5589
Justed picked up a Merc with what I thought was a seized powerhead. Turned out to be the lower unit. Removed the impeller housing, and put some penetrating oil on the top driveshaft bearing underneath the impeller housing .No go. Pulled the drain plug and some white goo visible on end of lower drain screw, but nothing dripped out. Tried to refil lower unit, it took a bit but oil wouldn’t come out the top vent?
Vice grip on the shaft won’t turn it. Anyone have any ideas how to unstick.
Thanks,
Bob DOctober 28, 2016 at 9:08 pm #46635disassemble it. they have needle and ball bearings in them. even if you get it to turn you need to open it up. believe me on this.
October 28, 2016 at 9:21 pm #46637Dave, do you need a special tool to get the ring holding the bearing carrier out?
October 28, 2016 at 10:53 pm #46644yes but you could make something to do the job. OR drill the ring 180 degrees apart and split the ring.
call me 1 914 310 7086.October 28, 2016 at 11:17 pm #46647I had a similar Mercury 4 with that problem. New parts, where available, cost a fortune, like $400. Used parts or assemblies were hard to find.
It’s all needle bearings. The needles will be bad, and whatever surface they touch will also be bad. I was happy to sell mine a s a "parts motor".
Long live Johnson and Evinrude, they got the job done with simple and inexpensive sleeve bearings. Why a sub 10hp engine needed a jeweled lower unit is beyond me.
October 29, 2016 at 12:15 am #46654quote Theodore:I had a similar Mercury 4 with that problem. New parts, where available, cost a fortune, like $400. Used parts or assemblies were hard to find.It’s all needle bearings. The needles will be bad, and whatever surface they touch will also be bad. I was happy to sell mine a s a “parts motor”.
Long live Johnson and Evinrude, they got the job done with simple and inexpensive sleeve bearings. Why a sub 10hp engine needed a jeweled lower unit is beyond me.
I thought that too when I did one, but the proof is in firing it up. No 10hp OMC will run with it.
October 29, 2016 at 2:28 am #46663Update…..moved the shift rod that goes into the lower unit from drive to neutral, and the prop spins freely, but the prop will not move when I move the rod to the left or right to shift into forward or reverse. I am now thinking some sort of mechanical problem causing the driveshaft to bind?
Dave, you are right, I have to take it apart. Will pick up the special wrench (Mercury C-91-30798) to remove the gear housing cover.October 29, 2016 at 10:20 am #46674You will need the wrench to put the cover nut back in but you usually have to drill and split them out, regardless. Why waste your money on a wrench when you may give up on this motor?
Up until 1975, Mercurys had steel drive, prop and shift shafts. The shafts pit where the seals ride on them, the seals go bye bye, the water gets in and you have the situation that you have. In salt water areas, this is the rule, rather than the exception. However, it also happens to fresh water motors when people don’t pay attention to the lower unit. On the really bad ones, you can’t even keep impellers in them because the drive shaft is so rusted that exhaust leaks into the pump and the impeller runs dry and burns up.They ARE great runners; but this lower unit situation is the sad truth. You may even have gears that are so pitted that they can’t even be reused.
You may find that you can get it apart, free it up and it will physically function without a lot of parts. Heck, you could even fill the lower unit with PB Blaster and hope it will free up. However, it will never be right or reliable (It may even self-destruct quickly) until it is all taken apart and virtually everything in it is replaced. (You can repair the drive shaft with a speedi-sleeve, which is a lot cheaper than a new drive shaft but still stupid-expensive for what it is.) Mercurys 1976 and up have very high quality stainless shafts, so this is no longer an issue. FINALLY! From 1976 on, Mercury Marine has never looked back!
Long live American manufacturing!
-
AuthorPosts
- You must be logged in to reply to this topic.
