1973 Merc 850 Power Head removal

[ShowMeGuy]

I decided to take a little deeper dive into the possible water in my #4 cylinder and maybe #3. And the not wanting to idle right after a dual carb rebuild with new floats and retiming/syncing. Here is what greeted me when I removed the power head from the base.

What would cause this to happen? A faulty base gasket? A endcap seal?
To me all the other parts looked OK to me.

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

Some more pics, of the progression.

Is there a way to get the end caps out with out splitting the case, per the Service Manual?

Thanks, interested in everyone's input. This is the first time I've opened up a Outboard..... But it all looked good to me, except the spot where the lower unit connects up to the crankshaft.

 

[Chris1956]

Re: 1973 Merc 850 Power Head removal

Endcaps can be removed., w/o splitting the crankcase. Loosen the crankcase bolts adjacent to the endcaps and the endcaps will pull off.

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

Endcaps can be removed., w/o splitting the crankcase. Loosen the crankcase bolts adjacent to the endcaps and the endcaps will pull off.

Yup..they come off with the correct threaded bolts... I believe these are 1/4"x20.

Which brings me to a few other questions. Do you think I need to look for a speedi-sleeve?
Before (as-pulled)

After (320G emery cloth)

What do you guys think? Speedi Sleeve or No? I'm thinking NO at this point.

More in next post....

 

[Faztbullet]

Re: 1973 Merc 850 Power Head removal

Yep... bad seals as that a fuel/oil /water mix you found and yes replace sleeve......and while your there remove the water lne on exhaust plate and plug with brass plug from center of water jacket, bring your "pee" indicator from center of water jacket up above #1 plug and back down to discharge as this will give you true water pressure and you will now block is filled..

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

Here is the end cap and the seals as they were removed. I recall somewhere saying they face opposite direction. These both look to be facing down away from the Crank. Is the bottom one supposed to have the seal/spring facing down toward the exhaust extention plate. And the inner to be placed facing the crank? They look to be original seals..... Here take a look as I remove them...

One down... one left.

Overall...

Hope these pics can help someone down the road if they don't help me out....

How do I install the seals when they get delivered??? IN the mean time I've got a lot of gasket prep work.

 

[1960 Starflite]

Re: 1973 Merc 850 Power Head removal

You are living up to your forum name, ShowMeGuy! I've never had a two cycle powerhead apart (other than a chainsaw), but I've installed a lot of seals in my job as a machine repairman for Rockwell Int. (retired after 30 years). I would think you are correct in you statement as I would install one lip toward the combustion chamber and the other lip towards the exhaust/water area. As to the speedie sleeve, when in dought do it, in my opinion.

Would you please post the part numbers required for this job when you are finished? I would think you could purchase bearings and seals from a local bearing supplier. IE: Applied Industral Technologies, Bearings Inc. I'm bringing a 1975 850 back to life and I do hope I don't have to go where you have been.

Tom on Buckeye Lake

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

Yup.. Will do Tom! I'm waiting on the majority of the parts from Crowley Marine..... Not sure I'll do biz with them again as their website noted it was all instock if recall.. Still haven't shipped a thing as of yesterday and I ordered/paid on last Tuesday.....
I'll probably edit one of my posts and add it in there as well as a reply in the forum/blog post.

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

I ended up putting the bottom seal back in as it was found. The spring/lip towards the lower unit. Just like it was below when I removed it all.

Now something different than how the pic shows below. Sorry no pics of the actual install. I ended up putting the top seal back in a little different than the way it was found. I put it in reversed, the spring/lip towards the power head unit. Seems to make sense to me. Does anyone disagree?????

.

How do I install the seals when they get delivered??? IN the mean time I've got a lot of gasket prep work.

Summary. I ended up putting the bottom seal back in as it was found. The spring/lip towards the lower unit and the upper seal back in with the spring/lip towards the powerhead.

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

I also got all the plates cleaned up for install once the gaskets finally show up hopefully tomorrow.

I also ran my bottoming tap into all the holes and blew them out with compressed air.

The Service Manual states to put some epoxy back onto the bolts for the plate installation? What type of epoxy? Can a guy use Locktite? if so what number locktite?

Thanks in advance all!

I'll post pics of the plates and block clean up tonight... Promise!

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

OK, now I'm thinking I need to get that seal out and put it back in as I remove them from info on this website....... I've heard it go both ways to may times......

http://www.screamandfly.com/archive/index.php/t-242412.html
Probably the most overlooked and most common is the lower seals. To replace them the block does not have to come apart. The lower end cap can be removed with a simple pulled. Replace the seals using some perfect seal around the outside case of the seals and pack grease between the seals. They must have both lips facing down! Very important. If the end of the crank is buggered or rusty a speedy sleeve can be installed. The actual location of the seals can be changed to avoid any small grooves in the speedy sleeve.

HELP!!!!

 

[Moody Blue]

Re: 1973 Merc 850 Power Head removal

I'm certainly no expert but all the literature I've read indicate to install BOTH seals with the lip facing away from the powerhead. I have disassembled two 1971 Merc 800 motors and each of them had the original seals installed this way. Pretty sure Merc got it right when they put these motors together 40 some years ago.

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

I removed the end cap and put it back like I took them out. Both facing down away from the powerhead. Filled the space between them with marine grease and greased up the new o-ring and put it back.
Today I'm going to try to get new bolts for the inner water plate and all the baffle plate and cylinder head plate.
Wish me luck. I picked up a in-lbs torque wrench as well... and some red and black gasket sealant...

 

[Maxz695]

Re: 1973 Merc 850 Power Head removal

I believe that the seals where put that way for a reason. ther are 2 in case 1 fails. Unlike an engine with seals to hold oil in this is not nesecary on the outboard. These seals are meant to keep water out. That is why they are both placed with the lip out.

 

[ShowMeGuy]

Re: 1973 Merc 850 Power Head removal

Well I hoped to have this all buttoned up the other night but guess what. Good ol crowley marine didn't ship my cylinder head plate gasket.... GRRRR.. man I'm so sure I"m not using them for parts again...
I got the inner water jacket plate installed.

Along with the exhaust plate

Then a few important hand tools for assembly.

My cylinder head plate waiting on it's gasket..... DangIT

 

[Maxz695]

Re: 1973 Merc 850 Power Head removal

Looking good