Pre-alpha Merc140

[brucec]

I think I have an MR140 Drive unit on my approx 1985 century.Serial # for transom drive unit is A382065<br />I think I have some U-Joint knock as there is a knocking sound when the trim is way up. I have to run with trim up to get out to deep water. How does one tell if the U-Joints are bad versus needing the C-Clips. The manual says If U-joint knocking is suspected, inspect for evidence of bearing caps hitting center socket. What is the evidence they are talking about? If they are very bad I will be able to tell. But how do I tell if marginal? Is any play allowed? Can I buy a permenently lubed U-joint replacement? I would rather buy a whole U-joint assembly rather than try and press bearings etc. If bad I will have to take off the top cover.Where does one get the socket to remove the 4 topcover screws, They kind of look like an inverted torx. I didn't see the tool listed in the 6A3R3 pdf of the merc manual.<br />Any help would be appreciated

 

[Trent]

Re: Pre-alpha Merc140

First off... Do not take the four bolts off the top of the outdrive! Thats not were the u-joints are. (by the way its a twelve point socket) To check the u-joints your going to have to pull the outdrive off the boat. You are going to need a manual for your drive before you go any further. The MR drive will have a "A" stamped on the end of the propshaft. I personally do not like the u-joints you cannot grease because you need to pull the drive every year or so to check the u-joints and gimble bearing and bellows.<br />You dont need any looseness in the u-joints at all. Any good auto mechanic can help you replace the joints without changing out the whole setup... That would be overkill and $$$$$$

 

[brucec]

Re: Pre-alpha Merc140

I know thats not where they are. The manual shows<br />removal of the top cover when you have to replace the u-joints. When you say change the whole set-up I lost you. I would look to replace the u-joints with new ones and have the other rebuilt for spare-my use at high tilt will require frequent change-out. The permanent lube point is well taken. Why would I need a manual different then the on-line one? Is there a service manual better then the on-line merc manual? What about the c-clips? The manual talks about adding them to certain drives- is mine one that didn't have them originally?

 

[Grayhorse]

Re: Pre-alpha Merc140

Ditto the advice from bdc, don't remove the top cover of your outdrive. You only need to remove it to replace the u-joint yoke/input shaft if it's defective. Before you replace anything, make sure your trim limit sender is not out of adjustment for your outdrive. It's possible you are trimmed up too high, and the u-joint yokes are kissing. The trim limit switch normally prevents overtrimming, but can be out of adjustment.