War with lower unit

[Bosunsmate]

Re: War with lower unit

Actually i think that bushing is at the top of your first photo.

 

[Yesterday]

Re: War with lower unit

Soooo I got industrious and removed this exhaust extension plate. OMG these Mercs are built rather solidly!! It's all good though since I intend to change the whole pivot mount and learned I'd have had to do all of this anyway. This bushing you mention.. that harmless thin little piece of pretty shiny metal Is that what you're referring to? Have a look at it with the ext. plate off. And then enjoy what happens with a little upwards pressure on the L/U does. Alas that little harmless looking bushing (yes it was rotating with the shaft though I think it's not supposed to - investigating that now.) was the culprit!!

 

[Yesterday]

Re: War with lower unit

 

[mercurymang]

Re: War with lower unit

Don't you wish you could get paid big bucks to fiddle with that thing?

 

[Yesterday]

Re: War with lower unit

@mercurymang:
LOL truth be told, though I hate automotive mechanics, I actually enjoy working on small engines, so I don't mind. A little extra cash wouldn't hurt though!

@Bosunsmate:
just confirmed that part number, yup you nailed it.

Thanks everyone for all of the help! You've been stellar! I wonder should we ring off this thread, Or should I keep updating the whole rebuild?! Somehow I can't help think there's going to be plenty of interesting times to be had once inside that LU!

Also: Any advice on other parts I should order while I'm in there? I got the bushing and the gasket thus far.

 

[Bosunsmate]

Re: War with lower unit

Hope you gave it a bit of a jab in the guts for doing that.
im pretty sure you will need a few answers regarding the LU, maybe not, i recommend doing the seals under the waterpump housing especially.
The carrier bearing and retaining nut will most likely need heat to remove and it needs a lot of torque (i think its actually needs well over 100foot pounds), when you reinstall otherwise the clutch dog will slip and wear it all out quick smart. It wont even go into reverse with low torque to and just sits there spinning stripping the dog.
New thread or continue- up to you.
If you get the old seals out, if you email the dimensions to an enginneering shop or find the dimensions for the original parts on the internet you will get the seals for a lot cheaper than buying elsewhere i find. Just make sure you get the steel rings replaced by rubber o-rings by the shop


Enjoy the LU repair while on the couch!

 

[Moody Blue]

Re: War with lower unit

Not sure what the 23-27132 bushing is, but the piece you are seeing on the driveshaft is a seal carrier that is pressed into the bottom end of the crankshaft. Inside the carrier is an o-ring which is to seal water out of the driveshaft splines. EMCKELVY described it in his post earlier.

Looks like the corrosion on the driveshaft pulled the carrier assy out of the crankshaft when you dropped the LU.

The items of interest is #4 and #5 in this link

Mercury, Mercruiser, Force, etc. - CRANKSHAFT, PISTON AND CONNECTING ROD - MERC 850 (4 CYLINDER)

 

[Yesterday]

Re: War with lower unit

@Bosunsmate:
LOL well more like the basement as opposed to the couch!! Not sure the better hald would be happy with me greasing up her couch

@MB:
Ahhhhhhh now the picture becomes much more clear!!! I had read EMCKELVY's post but didn't draw the connection! I'm glad I was too late to order the parts earlier today, else I'd have been kicking my own backside after reading this!! Hmmm seems to me a semi sacrificial part did what it's supposed to, or at least I hope it did!! Time to revise my parts list I guess. I'm not going to try to salvage that carrier I don't think, It just doesn't seem all that practical.

Once again a huge thank-you to you folks!! Tomorrow (I think) should prove to be an interesting day. I'm so not looking forward to the spanner nut removal!!

 

[Bosunsmate]

Re: War with lower unit

I couldnt agrree more than what Moody Blue just said, sorry if i put you wrong. I think that bushing i thought it was is the one at the top in your first photo at post #78.
Off boating, only ice here is in my fishbox.
cheers

 

[Bosunsmate]

Re: War with lower unit

If you heat it up and chock the prop under the cavitation plate it should come loose. i think its a 24mm nut (or the closest imperial size to that, i use a 24mm though)- just keep adding a longer extension pipe on the spanner.
The prop will probably need a bit of heat on the shaft and a gentle knock with a rubber mallet to knock it free.
Take it easy then as the bearing carrier retaining nut (#52699) and the bearing carrier are the last hurdle but the biggest, however with the right technique, maybe some heat too, and not being reckless like wacking the side of the lU it should come free too- then your in

 

[Yesterday]

Re: War with lower unit

The prop is off. I tried using a punch to tap the spanner nut but it's not moving. I will have to make a tool for that I guess. Ive seen some made from ABS piping but given the amount of torque, and that mine has been in salt water for an unknown length of time, I don't think ABS will work so well.

Im envious you're in the water and I'm shoveling snow!! Enjoy mate.

 

[Moody Blue]

Re: War with lower unit

@Bosunsmate: Tomorrow (I think) should prove to be an interesting day. I'm so not looking forward to the spanner nut removal!!

If the nut is the original and never been removed before, you are in for a fight. Most likely you will end up drilling the nut in two places to split it. Watch the threads on the LU. If they are badly damaged then the LU is toast. ABS will NOT do the job. You can buy the proper tool from ebay for a "reasonable" price but many just drill it out. http://www.ebay.com/itm/MerCruiser-..._Accessories_Gear&hash=item4abf90f9c8&vxp=mtr

Once the carrier nut is off (one way or another), the next hurdle is to get the carrier assy out. Again, it will be a battle. I made up a custom adapter to bolt a slide hammer to the prop shaft. Took some serious pounding to yank the carrier assy out. Others have devised a puller to brace against the LU housing while pulling up on the prop shaft. I've pulled three of them apart, and all were a battle.

Take note of any shim material and where it came from. They must go back in the original location to preserve the gear mesh and backlash settings.

Good luck.

 

[emckelvy]

Re: War with lower unit

WOW! That's gotta be One for the History Books! Never seen a driveshaft rusted like that and pulling the O-ring carrier out of the crankshaft! Well, at least you got to the root cause of the problem!

I agree that if the lower unit is as bad as that driveshaft, you're gonna have a heck of a time getting it apart. Likely you'll never get the gearcase cover (threaded 'carrier nut') off with any tool, at this point I'd drill carefully and split it out, as suggested.

If you have a propane or MAPP torch, when it comes time to pull out the bearing carrier, it'll help to heat up the gearcase. It'll bind somewhat at the very rear of the carrier (the part the gearcase cover threads down against), but worse is at the forward end, where it butts up to the machined ridge in the gearcase. There's a big fat O-ring seal in there, and a wide flat surface where salt will build up. Makes it really really tough to get out. Heat and a slide hammer are the best chance you have to do it, though.

If the gearcase isn't cracked, and the threads aren't all stripped out, you can clean up the internal threads to accept a new threaded gearcase cover. Sometimes a mechanic's scribe will get the salt/deposits out, but yours probably is so loaded up with corrosion products that you might need to use a "thread file" to clean 'em up.

Here's an example:

Thread File - webBikeWorld

Amazon.com: KD Tools (KD 2249) SAE File Thread Restorer 8 Sizes: Home Improvement

Not too expensive and does a great job of getting all the gunk out, and straightening any bent threads.

As corroded as your lower unit is, you might do better by finding a parts motor on your local Craigslist. Later models (from around '69-'71) "650" 4-cyl models have a 2.3:1 gear ratio (as does your 850); also the 4-cyl "800" any 4-cyl "850", "85", "80", or "75" will have the correct ratio.

Worse case, if you can't find one of those, most of the Inline Sixes had a 2:1 gear ratio and you'd have to get a prop with a 2"-or-so smaller pitch than what you have now. But these Fours really like the 2.3:1 gears and perform best with those.

Sometimes you'll find a hot deal on eBay, but the parts generally run quite $$$, especially with shipping.

Heck, I just saw an old 650 Merc in my local Craigslist for $75, they're out there!!!

HTH & Have Fun!..........ed

 

[Yesterday]

Re: War with lower unit

If the nut is the original and never been removed before, you are in for a fight. Most likely you will end up drilling the nut in two places to split it.

Funny you say that! I've already drilled the holes in anticipation of having to do that.

Once the carrier nut is off (one way or another), the next hurdle is to get the carrier assy out. Again, it will be a battle. I made up a custom adapter to bolt a slide hammer to the prop shaft. Took some serious pounding to yank the carrier assy out. Others have devised a puller to brace against the LU housing while pulling up on the prop shaft. I've pulled three of them apart, and all were a battle.

I was pondering the possibility of drilling into the carrier and tapping the holes and then making a simple puller, but I came to the conclusion that if that was a safe way to do it, someone else would have already thought it up and used this method before me. I hadn't thought about the LU housing sort, thanks for the idea! I will give it some thought and see what I can devise. I flat out refuse to use the Seloc manual's suggested "prop shaft in a vise" method!

Take note of any shim material and where it came from. They must go back in the original location to preserve the gear mesh and backlash settings.

Duly noted! Thanks a bunch for the luck wishes, And the suggestions. I'll take all I can get at this point!

 

[Yesterday]

Re: War with lower unit

WOW! That's gotta be One for the History Books! Never seen a driveshaft rusted like that and pulling the O-ring carrier out of the crankshaft! Well, at least you got to the root cause of the problem!

That'd be my luck!! If not for the fact that I'd dropped $600.00 for this thing, I might have given up some time ago. Now that I'm this deep into it, I figure I might as well keep digging till I get to the other side!!

If you have a propane or MAPP torch, when it comes time to pull out the bearing carrier, it'll help to heat up the gearcase. It'll bind somewhat at the very rear of the carrier (the part the gearcase cover threads down against), but worse is at the forward end, where it butts up to the machined ridge in the gearcase. There's a big fat O-ring seal in there, and a wide flat surface where salt will build up. Makes it really really tough to get out. Heat and a slide hammer are the best chance you have to do it, though.

I have a propane touch and a few cylinders on hand for the event! Here's to hoping!!

If the gearcase isn't cracked, and the threads aren't all stripped out, you can clean up the internal threads to accept a new threaded gearcase cover. Sometimes a mechanic's scribe will get the salt/deposits out, but yours probably is so loaded up with corrosion products that you might need to use a "thread file" to clean 'em up.

Here's an example:

Thread File - webBikeWorld

Amazon.com: KD Tools (KD 2249) SAE File Thread Restorer 8 Sizes: Home Improvement

Not too expensive and does a great job of getting all the gunk out, and straightening any bent threads.

Well well sir! Aren't you just stogged full of useful information! To be honest I didn't even know such devices existed! I Appreciate that! Around here I suspect they may be generally useful tools to have on hand anyway. Thanks for that nugget!

As corroded as your lower unit is, you might do better by finding a parts motor on your local Craigslist. Later models (from around '69-'71) "650" 4-cyl models have a 2.3:1 gear ratio (as does your 850); also the 4-cyl "800" any 4-cyl "850", "85", "80", or "75" will have the correct ratio.

Worse case, if you can't find one of those, most of the Inline Sixes had a 2:1 gear ratio and you'd have to get a prop with a 2"-or-so smaller pitch than what you have now. But these Fours really like the 2.3:1 gears and perform best with those.

Noted! That answers a few other stray questions which were breezing through my mind!! Again, thank you for that!

Heck, I just saw an old 650 Merc in my local Craigslist for $75, they're out there!!!

HTH & Have Fun!..........ed

See my above comment and what I paid for mine, and then picture my face as I read this!!! LOL
I've been keeping my eyes open, but there's not much around here right now. I spotted a 50HP locally for cheap but found out per a previous thread that the LU wasn't useful to me. Close, but no cigar, as they say!

Thanks again!!

@MB:
About that spanner nut wrench, I don't know if you're aware but Sierra makes one that retails somewhere around $45.00 CDN. I Hmmm'd and Haaa'd getting one but figured it wasn't worth it for a single use. However, since my goal is to switch to having 2 Merc's (a backup) and happen to have a 402 sitting in the "project line-up" it may well be worth my investment, afterall.

 

[Yesterday]

Re: War with lower unit

OK so some spline cleaning with a dremel & wire brush, a few mins with a torch and off the carrier slipped. Any opinions on these shafts??

 

[Yesterday]

Re: War with lower unit

 

[Yesterday]

Re: War with lower unit

I'm now wondering if it's wise to reuse the carrier which caused all this grief. It cleaned up pretty well. I've also swapped the swivel mount for another with PT&T. Glad I did because the one that was on it was worse than I'd expected. I'm beginning to think this thing's had a rough life.

 

[Yesterday]

Re: War with lower unit

 

[Yesterday]

Re: War with lower unit

And so now the real trouble begins. the shift shaft cleaned up reasonably well. Surprisingly so actually. The drive shaft on the other hand..

See pics next page. -------------------------------->