1980 V4 115 Johnson Lower Unit Shift Cover

[yt]

Hello, I had a mechanic reseal my lower unit 2 years ago. Fist time I put in afterwards the water pump didn't pump though it tested fine on land. Had to haul it back to him. He claimed corrosion issues.. Then after only a few times in the water it started leaking more lube than before. According to him the shift cover bolts were corroded and couldn't be removed. So I decided to take it on myself. Pulled the lower unit (just love that shift rod screw) and one of those shift cover bolt heads was sheared off. I was able to get the rest of the bolts out no problem, pulled the cover and simply using vise grips removed the broken bolt. So basically he lied and didn't do the job right by replacing that shift cover/seal when resealing the lower unit. Probably sheared the bolt head by having his air ratchet set to tighten :mad-new: I ordered the parts but need to know the torque spec for those shift cover bolts and anything else I should know about replacing it. I see theres an o-ring for the shift rod that looks like it goes under the cover. Does that go into the cover somehow or just float on the rod? Also any tips on replacing the water pump. Thanks.

 

[Joe Reeves]

Re: 1980 V4 115 Johnson Lower Unit Shift Cover

Shift Rod O Ring...... There is a groove within the brass sleeve that the shift rod passes thru. The O Ring must sit in that groove, otherwise it would be impossible for it a seal to exist between the rod and the brass sleeve.

Tip of replacing the water pump? I always replace the entire water pump assembly to make sure it is as good as new and functions as such. Too much work to do twice.

 

[multimech]

Re: 1980 V4 115 Johnson Lower Unit Shift Cover

The max torque on those screws is 120 INCH pounds. I always go snug then a little more, you have a gasket to crush which seals the cover no problem as long as there is no corrosion on either sealing service. Needless to say don't use a pneumatic tool for this.

Your mechanic sounds like he is incompetent. Most water pumps will "pump" when they have pressure from a garden hose going through them.

Here is a helpful tip. Use a adhesive to put the oring around the impeller cup. Let it dry. Put the impeller on the shaft and over the bottom plate. When the adhesive is dry, push the cup and housing down on the impeller as you turn it clockwise. It should seat very easily. Watch the oring as you do it to ensure it doesn't slip out. Use a little lube oil on the plates to make sure you have something for the impeller to move across the first time you fire the engine up.

 

[yt]

Re: 1980 V4 115 Johnson Lower Unit Shift Cover

OK, thanks for the info and tips. The mech said he had problems with the impeller slipping and the key. He went through two impellers before he got it working. He blamed it on corrosion. I had to use a dremel tool to cut the impeller center ring to get it off the shaft, it was completely jammed on there. Amazing it worked. This isn't the original lower unit. The original started eating metal so I found a used replacement. The motor is an '83, from the looks of it this is an earlier gearcase. Late 70's - 80. Is there a better way to test the pump on land? Have the hose on low pressure or I suppose if i Could find a big enough trash can.

Also when I removed the shift rod I did count the number of turns before it came loose. When I put it back in is that the right way to do it? Count the same number of turns?