[jimmy@wm]

Hey guy's, i just removed the lower unit on this '87 mariner 150 to inspect the water pump and noticed a lot of play in the driveshaft. It seems the bearing is loose in the housing causing a lot of side play in the driveshaft and also quite a bit of up and down movement. The bearing is tight on the shaft. Is this normal or do I need to look at replacing the lower unit housing or is there something else that can be done to solve this problem? All advice greatly appreciated on disassembly and reassembly of the driveshaft unit.Thanks , Jimmy

[gregmas99]

If you have excessive side play you may need to decrease the number or size of the shim/s under the top bearing cup, to bring it back to specs, or your top bearing could be stuffed or you have an excessivly worn pinion gear set. However this could be an indication of other problems as well. Was the metal cup insert in the water pump housing damaged where the shaft passes thru? The shimming and preload procedure is covered in the service manuals. Its not hard to do but you do need some specific tools. If you are not comfortable with setting up gear sets I would sent it out to your local outboard shop. If the lower unit has been run in salt you will probably have trouble disassembling it all to check it over.Greg

[jimmy@wm]

Thanks Greg,the metal cup didn't show any signs of the shaft cutting it nor did the seal or the top housing.I've just ordered the mercury manual and I'm pretty handy with a wrench.The oil did smell a little burned.Is it possible that the housing is worn causing the bearing to have this side play and what purpose does the shims play in eliminating the side play of the bearing? Thank for your help.Can I ask for your help on this should I have to tear this lower unit apart? Thanks Jimmy

[rodbolt]

hello leave the lower unit shimming to a trained tech with the proper shimming and preload tools. if the oil is clean and the magnet is ok the bearing is ok. bearings and gear sets dont give any warning before failing. the fit of that bearing to race is loose feeling. it has a lot of up and down play as well as side to side when the pump is removed. the old style merc lowers had shims on both sides of the upper bearing. the later style has a tapered roller bearing that is pressed on the shaft and the race is shimmied. it takes a special driveshaft preload tool to load the bearing for pinion gearbacklash and height checks. if this unit is a salt or brackish used model it may be a beast to remove the bearing carrier. anyway I dont mean to discourage you but if you dont have the tooling and your not familiar with setting up gears and checking backlash rolling torques and contact patterns I dont recommend the do it yourselfer to adjust gear set.but your getting a manual so your on the right track. good luck and keep posting

[gregmas99]

Also good advise from Rodbolt, unless your comfortable with this sort of thing it is a job for people who know whats happening. The reason for the q about the pump housing metal cup, is that I have seen lower units operating fine with so much slop in the shaft that it chews out the metal insert in the pump. As a guide if they do that there ready for a rebuild. However yours sounds fine, as long as the oil looked like oil and not like milk you should be OK with a new pump kit. Just a hint, buy the full kit not just the impeller.Greg

[jimmy@wm]

Thanks guy's , I haven't removed anything but the water pump yet. I was just curious as to the play in the bearing.As for having it built in this area, I have already been told by the dealer that if they removed anything that was reusable it would be reinstalled and I would be charged for a new one anyway, so I don't really trust them. The only reason I actually pulled the LU originally was because the guy said that at high rpm the motor would start to overheat. Rod- where is the magnet you are talking about, or are you refering to checking the oil after it has been drained with a magnet? Thanks Jimmy