Lower unit rebuild - 1974, 4hp

[scott_maier]

Hello,

I've got two lower units for a 6hp, 1974 motor, one is basically junk and I am using it for educational purposes and possibly parts. The other I want to check out and make sure it is good to go. According to my manual there is supposed to be a spring and two detent balls under the clutch dog that you catch with your hand as the clutch dog is slid back. I didn't see the spring or detents on either of the two units I have. Is this normal or am i missing the parts?

My next question...both water pump housings have grooves on the inner surface where the impeller tips would be rubbing. The grooves look like rough lathe work. Is this normal for these water pumps?

Thanks in advance,
Scott

 

[crxess]

Re: Lower unit rebuild - 1974, 4hp

Okay, are you working on 4hp(Title) or 6hp(Text)?

'74 6hp parts shows Clutch dog and thrust washers at each end, but no ball spring assemblies.

Look inside the clutch dog. it is has 2 holes then it could take the spring and ball in each to keep dog in position on shaft. Does the shaft have a tapered groove near neutral center position? If not, the springs/balls have no function and are not needed.

 

[scott_maier]

Re: Lower unit rebuild - 1974, 4hp

Sorry, I'm working with a 6hp. The clutch dog doesn't have any holes, and the shaft is not tapered so that question is answered...thanks. How about the grooves in the water pump housing? i assume the pump would work better without them....

 

[crxess]

Re: Lower unit rebuild - 1974, 4hp

Oops, forgot to address. The grooves ARE from wear. Very common. You can Sand the plate to dress it out, buy a complete water pump kit(plate is included) or let it ride for noe and see how it pumps. My 6hp is slightly grooved and still has Great water flow.

 

[scott_maier]

Re: Lower unit rebuild - 1974, 4hp

I have couple more questions. One of the gears has a hole in the side of the sleeve...is this just to allow oil to enter the bearing? I can't see from my pictures if something was supposed to go there. And the manual isn't showing anything either. I'm pointing at the hole in one of the pictures.

Also I was wondering if anyone had any tips on removing that top seal for the gearcase. Its also shown in one of the pictures. I removed the plate that holds the seal,(the water pump assembly sits on this plate) but haven't tried to take the seal out yet. I'm first going to see if replacement seals are still available before making a mess of this old one.

And finally there is a picture of the old water housing showing those grooves I was talking about.

Click on or copy and paste the below address and you should be able to access my photo album.

http://picasaweb.google.com/maierscott

 

[scott_maier]

Re: Lower unit rebuild - 1974, 4hp

Got the seal out and have a new one to put in. My manual says to use an alignment tool (p/n 390880) when putting the gear assembly back together. I can't find the tool online and was wondering what it does and if I really need it.

Anyone out there familiar with this tool?