reinstalling lower unit

[Dave K.]

Please read! Question: when reinstalling the LU, does the crankshaft seal go on before the steel collar or vs/vrs? which one is on top?


Now remove the six (1/2 inch hex head) exposed mounting bolts under the cavitation plate. The lower unit may just slide right down, or it may take a little persuasion with a rubber mallet. The black rubber crankshaft seal will probably come off the top of the drive shaft as well as the steel collar. If they stay up inside the midleg, lower the engine and they should just fall out. If not, tap and jiggle a bit. When you go to replace the lower unit, the collar goes on with the groove facing up and the rubber seal goes on with the beveled end up.

 

[gregmsr]

Re: reinstalling lower unit

The steel collar goes on first with the grooved side facing up. This groove is for the rubber seal to set down in. If you look closely at the rubber seal, you can see a "crease" inprinted in the rubber where it sit down into the steel collar. This helped me determine which way the rubber seal is turned.

When I had mine apart, I found the steel collar laying down in the LU casting and it had been down there I guess since someone last had it apart. I ran the motor for two years like that with no problems. So, that makes me think that this seal and collar are not very important anyway.

 

[Dave K.]

Re: reinstalling lower unit

Thank you Greg. If I can trouble you for a couple more questions...I have the 85hp, can I do this job alone or is two people better? And, am I better off getting a pump kit or just the impeller & gasket that goes under the steel plate? Big difference in price & I can do the impeller tonight & be on the lake this weekend. Thanks dave

 

[gregmsr]

Re: reinstalling lower unit

Well i'm certainly not an expert on this and only done an impeller change once recently on my 125hp. But I will help if I can.
This can be done by yourself if you are fairly healthy and can lift and hold around 50lb. Removing the LU, your ok by yourself. Now when putting back on, you need someone to help by turning the flywheel slightly to align the splines for the shaft to slip back into the crankshaft. That was the most difficult part of the job. The rubber seal and steel collar kept falling off when I inserted the shaft up into the leg.
I don't know the condition of your LU as far as corrosion, etc but you probably only need to purchase the impeller. The pump housing should be ok but you won't know until you take it apart. On my 125hp, I did not have to remove the SS plate so I needed no gasket. Not sure on a 85hp.

I'm sure others will chime in soon and keep searching this forum for more info.

Good luck!

 

[Frank Acampora]

Re: reinstalling lower unit

That rubber crankshaft seal is not very important until the first time you get a driveshaft corroded tight into the crankshaft. Then after a few "prayers" and remarks about its ancestry, you will appreciate the seal.

All three and four cylinder lower units are the same with the exception of gear ratios--so they weigh the same and are disassembled and reassembled exactly the same.

You can just throw in an impeller and see if it works, but while you have the lower unit off, why not remove the SS plate below the pump and check the condition of the bottom torpedo shaped plate? All it will cost you is couple of bucks for the gasket. Or make your own--it's easy.