1970 Mercury 50 general maint. question

[Camlee98]

I bought a Mercury 50 last year and have not started yet. I want to get at the very least a new impeller and change the gear oil.
Should I buy the water pump kit or just get the impeller?
If the kit do you guys like mallory or sierra better?
Anything else I should do before trying it for the first time?
Thanks

 

[oldman570]

Re: 1970 Mercury 50 general maint. question

The first thing I would do is check the compression and read the plugs to see if everything is good there. Then drop the LU and inspect the impeller and housing for ware before getting parts for the water pump. If the cup and plate are groved bad, it would be best to replace them now as it will save time later if they will not seal on a new impeller. As for parts my preferance is OME , then Mallory, then Sierra in that order for any part needed. If the motor runs good when started I would use Sea Foam in the first couple of tanks of fuel to help clean any carbon buildup and varnish that has setup since it was stored. JMO
Oldman570

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

Sounds like a plan thank you!

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

I'm working on pulling the lower off. I can't seem to get it. I've loosened/taken off three nuts. What am I missing?

This one

Two of these one on each side. There is a cover that I took off that I shouldn't have lol. I can't get it back on any tips?

Does this need to come off? If so how?

 

[79Glastron]

Re: 1970 Mercury 50 general maint. question

On your last picture, you'll need to remove that rubber expansion plug. You'll find either a 12 point head bolt, or an allen socket head bolt. Once that is out the trim tab can be removed and you'll find the 4th bolt holding the LU on.

 

[hotrod53]

Re: 1970 Mercury 50 general maint. question

Yep, the illusive 4th bolt is under the anode. Like 79 Glastron said, remove that plug, not sure why that is in there anyway, you need a long edxtension to get to it.

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

I figured that had something to do with it. Well I got that plug out but it wasn't pretty. I'll need a new one now if I can find one. It's a very large hex under that so I'll have to hit the auto store tomorrow. Hopefully I'll have it off after that.
Still gonna need some suggestions for getting that plate back on...I think it covers some sort of suspension?
Thanks for the help!

 

[GA_Boater]

Re: 1970 Mercury 50 general maint. question

The anode is held with a 3/8" allen. When you order parts get a new anode, it looks like the fin is broken off. Most motors don't have the plastic plug over the allen, long gone. Still available if you want to use one.

The cover is over the swivel mount and has a fairly stout spring behind it. Back out the screw (the one you loosened to take it off), hook the front of the cover and push hard on the cover toward the midsection and tighten the screw.

Some advice - Don't take things off if you don't know the consequences. The wrong bolt or screw taken off will cost a bit of time and or money to fix. This is meant to be helpful. Also do yourself a favor and get a manual. Good luck. If you take care of the old Merc, she will run just about forever.

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

I knew the don't take that off thing....I just didn't listen to myself. Lesson learned! Thanks for the advice! I'll check that anode again but I don't think it's broken? Pic 4 shows it better. If it is I'll buy another. Id that plug called a anode plug? If it's better to have it I'll get one if it really doesn't matter then I'll just move on.

 

[GA_Boater]

Re: 1970 Mercury 50 general maint. question

Missed the anode on pic 4, cam. It's good, looked busted off in pic 2, must have been the light or angle. On that plug - It's called "PLUG, PLASTIC - WATER PICK-UP SCREW HOLE". Less than $3 but most are gone. I wouldn't worry about it.

 

[79Glastron]

Re: 1970 Mercury 50 general maint. question

The anode is held with a 3/8" allen. When you order parts get a new anode, it looks like the fin is broken off. Most motors don't have the plastic plug over the allen, long gone. Still available if you want to use one.

The cover is over the swivel mount and has a fairly stout spring behind it. Back out the screw (the one you loosened to take it off), hook the front of the cover and push hard on the cover toward the midsection and tighten the screw.

Some advice - Don't take things off if you don't know the consequences. The wrong bolt or screw taken off will cost a bit of time and or money to fix. This is meant to be helpful. Also do yourself a favor and get a manual. Good luck. If you take care of the old Merc, she will run just about forever.

Right, 3/8" bolt, 1/4" allen socket head size.

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

Ok I finally got back to the motor. I pulled the lower end and it looks like a impeller change is in order.

So here are my next questions.
Should I pull the base off and if so any tips on getting it off? ( I bought the impeller kit so I should have everything I need)

Should I replace all of this or will I be opening a can of worms if I start pulling stuff off?

There's a small buildup of black hard stuff around this do I scrape it off? and how do you think this looks?

Does this base look ok to you guys?

What do I use to clean all of this stuff? Brake or carb cleaner?
And finally what type of grease should I lube this stuff with? Can I use the green marine grease I put in my bearing buddies?

Thanks for the help

 

[GA_Boater]

Re: 1970 Mercury 50 general maint. question

Cam - On the kit you got my thoughts are if you have the parts put 'em in. To remove the base the flushing screw is removed. I gently pried through the flushing port to get the base moving up. It can be tight with the O-rings. The two large O-rings go under the base along with a seal. My lower unit oil had some water and the base seal was shot causing the water in the oil.

I used a razor blade to get the rubber off the insert. I see some wear pattern on the insert but there doesn't seem to be any gouges. Prob OK.

What is your serial number? I get/find a link to a parts break-down.

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

Thanks GA! I was thinking the same thing but I didn't want to pull it off and find out it's one of the biggest pains in the but to put back on. Or it breaks stuff trying to get it out or something like that.
My SN# is 2738823

 

[GA_Boater]

Re: 1970 Mercury 50 general maint. question

Cam - Here's a link to a parts diagram. I used a little grease on the O-rings putting it back together so they didn't get cut..

 

[chum1]

Re: 1970 Mercury 50 general maint. question

use Vaseline to lube parts up as grease may deteriorate rubber parts, stainless cup looks ok, great pics and questions

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

Thanks chum.
Ok I've pulled the base and I also drained the gear oil which looked ok no water and no metal.
So on the top of the base is it suppose to be flat? Mine has a small groove and lip. I post a pic as soon as I can.

 

[Camlee98]

Re: 1970 Mercury 50 general maint. question

Here's a photo

 

[GA_Boater]

Re: 1970 Mercury 50 general maint. question

Cam - from memory I think a seal(s) fits in there. the O-rings seal the outside of the base to the LU housing and the seal is for the shaft. Items 14 & 15 on Gear Housing. page one in the link I sent earlier. It looks like some of the old gasket is still on the base.

BTW - When I said grease earlier, I meant to say lower unit oil. It sure shouldn't harm LU seals.

 

[WoodOnWater]

Re: 1970 Mercury 50 general maint. question

Very informative. I am working the same issue with a '73 500. Aaahhh, a fourth bolt. I stopped my assault and started seaarch and rescue and found this thread. I'm new to O/B's so this is great for me. I think I will be getting into the prop shaft seals too with mine, but I won't hijack the thread. Eager to see more.