Evinrude 1990 8HP lower unit separation and reinstall for impeller replacement

[Tim Frank]

I am replacing the impeller and when I removed the L/U the drive-shaft stuck in the powerhead and the lower end came out of the gearcase.
I have removed the shaft now and cleaned up the upper end.

Should I be able to just replace he shaft in the lower unit or are the seals going to be compromised?
Obviously I would rather not open up the gearcase if I don't have to.

The manual is unclear but the gearcase at this point has no issues and is watertight....or at least it was.....:facepalm:

 

[racerone]

Just slide the driveshaft back into the lower unit.----No issue.

 

[Tim Frank]

Thanks....what I was hoping.
I may be taking the gearcase apart anyway. The impeller key is MIA.
It sheared last fall but I have not been able to find it.

 

[oldboat1]

not sure if that '90 has an impeller pin or the traditional key (a little larger if you have to locate it). But I don't think you have to get into the gearcase. If it's still in the l.u., it's probably somewhere down in the water passage down in the skeg. A small magnet and flashlight would help -- and your reading glasses.

 

[Tim Frank]

Well I'll keep looking.
It is the key....there is a flat milled in the driveshaft.

 

[racerone]

It is a round stainless pin.----Never seen one that sheared..-----

 

[Vic.S]

It is a round stainless pin.----Never seen one that sheared..-----

I had plastic one with one after market impeller. A sort of flat triangular shape rater than round.

 

[Tim Frank]

It is a round stainless pin.----Never seen one that sheared..-----

You don't live where the water gets hard in the winter.
Still have not found the key, but it is clearly totally different from my 6HP 'rude which is indeed a SS pin that matches to a hole in the driveshaft.
My 8 HP....subject of this thread has a flat milled on the drive shaft and the picture of the key for it shows a strange looking beast.

As long as it is not in the gearcase i should be alright.

 

[racerone]

They used to be a stainless pin on the early models of that motor , the 7.5 hp starting in 1980.

 

[oldboat1]

Interesting. Closest thing I have right now would be a couple of ‘80s and early ‘90s 9.9s. Unable to remember what keys they have, so looked at a parts list and find a dowel or pin that rides vertically in a flat spot on the shaft. (Don’t know whether it’s stainless.)

Know what you mean by that odd shaped key — see that listed for your motor.

If it were mine, I might take the l.u. off and invert it, or maybe try to hose it out a little and see if anything comes out. Other than that, think I would just finish installing a new impeller and go.

 

[Tim Frank]

The lU is off now. I am waiting for parts to R&R the impeller.
I will backflush with a lighter oil and see if anything "comes ot in the wash....
Other than that, I will just reassemble and go.....until it stops.

 

[Tim Frank]

Last question: the manual (at the lake, so going from memory) specifies assembly details numbered 1-5.
Torques , lubes etc.
For the 4 waterpump fasteners there was an OMC product spec'd....a threadlocker, or term to that effect.
Any reason I can't use a service removeable Loc-tite or is the OMC stuff a super specialty item?

Thanks for all the input. Always appreciated.

 

[oldboat1]

My manuals are upstairs in the workshop (where I’m not), but confess I got into the habit of using a dab of marine grease or OMC gasket sealer on the housing screws. Never had issues — concern was corrosion related to salt water use, but I’ve continued to do the same in nice clear fresh water. Further confession — I like to use a box wrench and tighten the screws in a cross pattern, two or three passes until it feels right. (I don’t pull out a torque wrench for that.)

Of course, I would recite the service manual instructions if I had them handy…. Maybe another lister can do it for you (assume you want to put it together and go fishing).

 

[Tim Frank]

I was not actually asking for the instructions...the manual and motor are in the same place so I will have it to refer to if needed on reassembly.
What I was hoping for is an opinion on the manual's specification to use an OMC threadlocker. Is Loc-Tite 242 an equivalent?....that I do have in inventory...I would have to buy the OMC stuff; probably 10 years supply if it does not spoil.

 

[Vic.S]

I was not actually asking for the instructions...the manual and motor are in the same place so I will have it to refer to if needed on reassembly.
What I was hoping for is an opinion on the manual's specification to use an OMC threadlocker. Is Loc-Tite 242 an equivalent?....that I do have in inventory...I would have to buy the OMC stuff; probably 10 years supply if it does not spoil.

According to the Sierra catalog Loctite 242 replaces OMC500421

This page shows the other Loctite equivalents so if you know the OMC number you should be able to determine the equivalent Loctite product.
http://www.sierramarine.com/sierra/2018/2018sierracatalog.html#p=199

 

[Willyclay]

Could a Moderator post this info in the "Sticky" created for such questions?

https://forums.iboats.com/forum/eng...75-evinrude-engine-engine-gasket-sealers-list

 

[Tim Frank]

Thanks Vic. That anwers that.

 

[oldboat1]

Service manual instructions tell you to coat the screws with OMC Gasket Sealing Compound, install them, and tighten to a torque of 60-84 in lbs.

 

[Tim Frank]

To update and close this out, I have the new parts and the OEM key is/was plastic.
The BRP water pump kit has everything....including housing, bolts, and key.