'75 850 Lower Bearing

[mercurymang]

I ordered some parts last week for the 850 I'm working on. I replaced the two lower crank seals and o-ring noticed while I had it off that the lower bearing felt a little sloppy. Is that bearing supposed to be fairly tight (ie. no play)? I went ahead and put it all back together but I figured I would inquire as to whether or not anyone thought I should go ahead and replace it.

 

[bgc]

Re: '75 850 Lower Bearing

ZERO PLAY, its cheep, replace now. While you're in there do the top seals and bearings……..

 

[mercurymang]

Re: '75 850 Lower Bearing

Will that bearing come off without cracking open the block. Can I get it out via the end cap?

 

[bgc]

Re: '75 850 Lower Bearing

yes, its a tight fit

 

[mercurymang]

Re: '75 850 Lower Bearing

yes, its a tight fit

Any advice on how to pull it off?

 

[bgc]

Re: '75 850 Lower Bearing

You will see threaded holes in the End Cap, this is where the puller attaches to. Be careful and go slow.

 

[mercurymang]

Re: '75 850 Lower Bearing

You will see threaded holes in the End Cap, this is where the puller attaches to. Be careful and go slow.

I was referring to removing the bearing. I have the end cap off. As a side note, I have a same year 650 and i figured I would compare the serial numbers on the two. As it turns out, they are the same part number and they are in perfect shape. Now if I can just get them off, I'll be in business.

 

[bgc]

Re: '75 850 Lower Bearing

I bake mine in the oven at 170(when the wife wanes around to see it) and used a puller to get it out.

 

[mercurymang]

Re: '75 850 Lower Bearing

When I pulled my end cap, the bearing stayed on the crank. So when you pull your caps the bearing comes out with the end cap?

 

[emckelvy]

Re: '75 850 Lower Bearing

Many of the older motors have the bearing pressed into the cap and a slip-fit on the crankshaft. Your 850 has its ball bearings pressed onto the crank. Unless you can find a puller with thin enough jaws to fit inside the crankcases, and at the same time strong enough to pull the bearing, you're gonna have to split the crankcase.

All the ones I've taken off, I've had to use a bearing splitter-type of puller to get between the bearing and crankshaft counter-weight and make the initial busting-loose. After that, you'd use a jaw-type puller or a harmonic-balancer style of puller, with bolts threaded into the face of the bearing splitter.

If you're very careful, you don't have to remove the rotating assembly from the block. Just pull the crank out far enough to get the pullers on it, and be sure to prop the crank so it doesn't get damaged from rocking side-to-side.

Heat the new bearing to no greater than 250 Deg F (an old toaster oven works great for this), and slap it onto the clean, lightly-oiled crankshaft. Note you only have one chance to get this on straight, if you don't get it fully on & seated against the shoulder of the crankshaft before the bearing i.d. shrinks onto the crank, you'll have to drive the bearing the rest of the way. Never drive against the outer race, only the inner.

Clean/degrease the manifold cover & block sealing flanges; install new cork strip gaskets, and spread a thin coating of sealer on the block flange.

I like to use Loctite 518 anaerobic "gasket maker" http://www.summitracing.com/search/Product-Line/Loctite-518-Anaerobic-Gasket-Maker/

OMC Gel-Seal is pretty much the same thing:

Evinrude Johnson OMC 0324073 - Gel Seal @ MarineEngine.com

Mercury sells a similar product as well, called "Master Gasket".

I've had good luck with just the 518 sealer by itself. My local NAPA carries the stuff by the tube and it's not extremely expensive.

The 'old school' alternative to the anaerobic sealer is to use Permatex No. 3 Aviation-Type non-hardening gasket dressing; Mercury Marine, in the past, has said that is was OK to use on motors that had the cork sealing strips. I still prefer the 518 sealer as a modern alternative and have never had a leaking flange.

Recommend you install new crank seals in both upper & lower bearing caps while it's apart, might as well! Same goes for the bearing cap O-rings.

HTH & G'luck on the repair.

 

[mercurymang]

Re: '75 850 Lower Bearing

Ok, I'm going to procure a some bearing pullers cause what I have currently is garbage. I guess as a backup I could always try something like this.

 

[mercurymang]

Re: '75 850 Lower Bearing

install new cork strip gaskets, and spread a thin coating of sealer on the block flange.

Are you referring to the ends of the block between the gasket and the end cap?

 

[emckelvy]

Re: '75 850 Lower Bearing

Are you referring to the ends of the block between the gasket and the end cap?

The sealer is spread out thinly on the entire mating/sealing surface of the block. Anaerobic sealer only cures in areas where is is "squished", so there will be a very thin layer of sealer between the mating surfaces of the block and manifold cover, once the cover is torqued-down to the block.

If you're not going to "split" the crankcase, and are able to pull the bearing, as I recall Merc recommends a coating of grease on the bearing cap O-ring. I've used Permatex #3 in the past and I like doing that 'cause it seals out any salt that might get in there and cause corrosion issues. If you're not running in a salty/brackish area, that wouldn't be an issue. Just apply a thin coating of grease on the O-ring and maybe a bit on the bearing cap surfaces, it'll help when you reinstall the cap back into the crankcase.

Hope that clears it up................ed

 

[mercurymang]

Re: '75 850 Lower Bearing

I went over to HF and picked up this: Bearing Separator and Puller Set

However, the width of it is just a hair wide and ends up pushing on the outer portion of the bearing. I seem to be having a problem finding one of these much less one that works in this scenario. Do you happen to know who might carry one?

 

[emckelvy]

Re: '75 850 Lower Bearing

That's OK if it pushes on the outer race of the old bearing; the cautionary note about driving the bearing onto the shaft using force on the inner race only, applies to the new bearing installation. And that's only if the hot bearing happened to cool down too fast and got stuck on the shaft before it was seated.

BTW, I've never had a bearing get stuck. Once the bearing is fully heated (I leave mine in the toaster oven for at least 20 minutes at 240F), I've got a heavy set of leather gloves to grab the hot bearing out of the oven, then it goes right to the crankshaft. Slides right on, you've just got to be accurate and fast during the installation!

Pulling the old bearing off the crankshaft will cause permanent damage to the bearing no matter how you do it; it don't matter 'cause you're gonna replace it anyway.

HTH...........ed

 

[mercurymang]

Re: '75 850 Lower Bearing

Ok. I had two good ones from another motor I had so I was trying to pull them off non-destructively. Looks like they are only around $30 a pop. I'll just order some new ones. I'm planning on using some mapp gas to heat the old one and pull it off.

 

[emckelvy]

Re: '75 850 Lower Bearing

Here's a real good deal on a "206" ball bearing on eBay:

SKF Ball Bearing 206 | eBay

I usually get mine at NAPA but if you watch the eBay auctions, you'll probably find a good buy on a Fafnir, TRW, BCA, Bower, SKF, etc bearing. Those are all quality-built.

Just stay away from the Chinese-made bearings, they are cheap but I would never run that Junk in an outboard that I cared about!

Note that the bottom bearing is a "206" (aka "6206") whereas the thicker bearing at the top is a "5206" and quite a bit more expensive than the bottom, since it has a double-row of bearings.

Cheers...........ed

 

[mercurymang]

Re: '75 850 Lower Bearing

Interesting. I usually buy from iboats, or marine engine. Crowley is way overpriced. Marine engine list the bearing as part 30-63742T. So an skf 206 is the same part? I would never even have know to search by that number. And to your point, I generally by qucksilver parts.

 

[mercurymang]

Re: '75 850 Lower Bearing

I did some thinking found something interesting. I grabbed a light and a magnifying glass and found that the id on the old bearing is F.A.G. 6206. F.A.G. is a german manufacturer. Before I got into boating I was into bimmers. I have a couple of old ones and I thought that the bearing looked similar to the rear hub bearings on two of my bmw's. I did some cross referencing and found that sure enough, they are the same bearing. Who would have thought.

 

[mercurymang]

Re: '75 850 Lower Bearing

Ed, I purchased the 6206 you showed me on ebay. I have a question though. That bearing does not show any dimensions that I could tell so I figured that the 6206 designated dimensions. However, I was researching bearing cross references and found several 6026 bearings with different dimensions. How were you able to tell that the one you listed was the correct size?