War with lower unit

[Yesterday]

Re: War with lower unit

Thanks Gerry! You are a superstar! This looks way better than the Seloc I pissed away good money on!
Ahh so i's intentionally 2 pieces? Odd but that explains why the shifter seems to still work. (While they're in place at least).

Interestingly beneath those cams the shifter shaft looks half decent compared to up in the spline area, so I'm hesitant to cut it out. I wonder if my little propane torch is just not getting hot enough to help the situation? That it's -12C here probably doesn't help matters.

 

[Bosunsmate]

Re: War with lower unit

Keep on heating, its a tight fit to start with so the rusty gunk will make it hesistant to move. its about an inch long in there.
The splines always look rough where it joins but its a tight fit in there and they seem to come out very clean. Mine looked worse and now looks like new as that rust just polishes off.
Ive seen them split with the connector actually coming off the splines in the topshaft and still being seized in the bottom

 

[Bosunsmate]

Re: War with lower unit

if it was me id put two long thin candles in there and leave them heating that sleeve from the bottom up along it for at least twenty minutes JMO

 

[Maxz695]

Re: War with lower unit

Take the roll pun out of the shift bracket up top and with luck the hole shift rod will slip out and then you can tackle it from there.

 

[carholme]

Re: War with lower unit

The two piece cam is only there to raise the rod for the reverse lock so that the engine does not rise when you select reverse gear.

If you look under DRIVE SHAFT HOUSING ASSEMBLY, items 12/13 and 14, 13 is the rod that the cam pushes up when you select reverse. Attached to the other (upper) end of the rod is item 26 under CLAMP BRACKET AND REVERSE LOCK. So the rod rises and the hooks grab rod, item 28, preventing the engine from rising.

What is holding your shift shafts together is corrosion in the shift shaft coupler, item 15 under BOTTOM COWL AND SHIFT LINKAGE.

Gerry

 

[Maxz695]

Re: War with lower unit

Yes gerry I saw a 2 piece cam as well
with an iron shift shaft and more than likely drive shatf. Up ad down work it up and down thats why I stated tip it over. Your correct 2 peice cam

 

[Yesterday]

Re: War with lower unit

Ahhh thanks Gerry, for a while I was thinking the gearbox needed some odd lock to keep it in reverse, but that makes more sense. LOL

Thanks for the suggestion Maxz and in fact everyone. I think I will try and pull the whole rod out. It looks like the attachment on the top of the rod is held on with a set screw? They don't shoe anything in the parts diagrams so I'm basing that on a pic of the part from ebay. It may be a pain in the butt to get out that way but it'd be a lot easier to get apart once it's out of the midsection I'm sure!

In my second pic it looks as though the coupler for the shift rod is also attached to something in front of it? I'm hoping that whatever it is, it will also slide down and out?

 

[Maxz695]

Re: War with lower unit

Once you remove the screw or roll pin there it should come out fairly easily. I find it easier to remove the cable barcket to get to the screw or pin. I used a 3 inch roofing nail with the point cut off with a pair of dikes to flatten it out to tap the pin through. Brace the lower unit when removing because it,s going to drop right out or may need some slight persuasion. If there is extensive corrosion in the steering tube it may get stuck there and not come out as well. I had to cut the one from my 70 HP to separate it at that point.

 

[Moody Blue]

Re: War with lower unit

Any success?

 

[emckelvy]

Re: War with lower unit

I haven't looked at this thread for a few days, Man is that shift shaft rusted!!!! Probably terminal but you'll need to get the lower unit dropped to fully evaluate.

The reverse lockout cam and the reverse lockout rod plastic guide are relatively inexpensive parts and you're gonna want to replace them anyway.

So, don't worry about burning them out. They're gonna smoke a lot so don't breathe the nasty fumes! Have water and a fire extinguisher handy.

The aluminum shift coupler has splines on both ends, so once the coupler gets hot enough it's gonna expand and you'll be able to get the lower shift shaft separated from the upper.

One thing you might try, since you have some space to work with, is get a set of Vise-Grips firmly clamped on the lower shift shaft. Heat the living daylights out of the aluminum coupler, dunno if you can get it hot enough with propane to melt aluminum but it'll sure soften it up. Then you can wedge the lower unit a bit and also give a good downward rap on the Vise Grips, this should help bust the rust/scale buildup on the alum coupler and help break 'er free.

Rapping downwards on the shift shaft also helps keep the shift shaft in the lower unit. The only thing holding the lower shift shaft in the lower unit is an "E" clip in a groove, riding against the bottom inside of the shift seal/bushing assembly. Very easy to put too much prying force on the E-clip then it'll jump the groove, and out comes the shift shaft. You are probably gonna have to replace that shaft, but you don't want it to come out until you properly position the propshaft & gears for removal of the shaft. If the shaft accidentally pops out, it's rather a pain to get a new shaft in without dismantling the gearcase.

Just be cautious when rapping on the shift shaft, since it can bottom out in the gearcase and the downward force has the potential to break things as well, since the shaft can bottom out and transfer that force to the structure inside. Normal force isn't likely to hurt anything.

If you can get the aluminum coupler hot enough, it shouldn't take a lot to get things loose, at any rate. Aluminum expands at a much faster rate than the steel shift shaft & upper shift rod.

Let us know how it goes and when it comes time to install a new shaft, we can walk you thru that as well.

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

 

[Yesterday]

Re: War with lower unit

So the war resumes!! After some time away due to work, blizzards, and well life itself, I finally had a chance to get into the garage and put some more effort into this. I pulled the breather and the carbs, made a custom punch to get the pin out of the shifter shaft up topside and that went well. I then used another punch to tap the shifter shaft out of clasp and it slid out with relative ease. Looking from down low the shaft had dropped pretty near an inch back into the gearbox. Alas some excitement! Will this LU finally slide out?? Hell no! So, I rotate the flywheel some by hand and the prop shaft is not turning. I try to turn the shaft itself, click click click - one way, won't turn the other. I'm thinking, this is good right? gearbox is in gear? OK so if it's in gear and yet rotating the flywheel doesn't spin it, doesn't that mean the crank and drive shaft have been parted? And since the shifter shaft is moving relatively freely, it's not seized. What the hell can be holding this? The rubber gasket holding the exhaust can is completely free and all the studs are definitely moving freely. I look again and see that aft of the drive shaft itself is a tube which I'm thinking is a water tube. I actually see a seem in it which makes me believe even that's separated.

To the hand, it still feels like it's the drive shaft itself thats not coming free, but isn't it basically hanging loose once it's out of the crank up top?

Any chance there's a cut-away or diagram of the middle unit? I'm thinking perhaps the drive shaft is hung up on a bushing? or a close-to-size passage way or something?

Frustrating!!!!

 

[Moody Blue]

Re: War with lower unit

You've certainly got a battle on your hands. Quite puzzling.

It does sound like the driveshaft is free of the crankshaft splines, and if the shift shaft and exhaust tube are free, there is virtually nothing else holding the lower unit on. The water tube as you mentioned is a free floating copper tube that slides into a rubber grommet up top and the lower end just "slips" into a guide tube on the top of the waterpump. The watertube sometimes comes out with the lower unit and sometimes stays with the powerhead.

How much has the lower unit dropped? Is it possible to repeatedly raise and drop the lower unit in an attempt to jarr it free?

 

[Yesterday]

Re: War with lower unit

You've certainly got a battle on your hands. Quite puzzling.

It does sound like the driveshaft is free of the crankshaft splines, and if the shift shaft and exhaust tube are free, there is virtually nothing else holding the lower unit on. The water tube as you mentioned is a free floating copper tube that slides into a rubber grommet up top and the lower end just "slips" into a guide tube on the top of the waterpump. The watertube sometimes comes out with the lower unit and sometimes stays with the powerhead.

How much has the lower unit dropped? Is it possible to repeatedly raise and drop the lower unit in an attempt to jarr it free?

It's dropped a lot, as I can see air between the bottom of the leg and the rearmost studs. Pretty much per the pics. Getting it down that far took the better part of a whole day though, so I'm really hesitant to start that business all over again! I'm halfway thinking I might just have to hoist this puppy by the LU, but I'm leaving that notion as a last resort deal.

 

[quicktach]

Re: War with lower unit

Penetrating oil can do wonders for a rust frozen connection. Kroil is superb too. Let it soak a day or so before trying to work it apart.
If you have to heat it and you can get close to it, you could use a brazing torch (hotter).

 

[Yesterday]

Re: War with lower unit

Penetrating oil can do wonders for a rust frozen connection. Kroil is superb too. Let it soak a day or so before trying to work it apart.
If you have to heat it and you can get close to it, you could use a brazing torch (hotter).

Agreed. I have seafoam, but I'm not sure to what I should be applying it?! Also gravity would have to be a factor so that would mean inverting the motor for sure I guess.

 

[Bosunsmate]

Re: War with lower unit

Seems like you are closing in on winning it.
Put a lock wrench in and on to the driveshaft, see if it can rotate clockwise when you have no weight on the lU. Try it again with weight on the LU and see if that makes it more difficult.
There is a groove on the splines for an o-ring, normally those have disintegrated by now. If its being run in salt? A deposit may of built up around the bottom of the end cap but if its dropped a bit i cant see why it wont drop more through that because i dont think the splines are more proud than the rest of the shaft (from memory).
Possibly the shaft is bent there

 

[Yesterday]

Re: War with lower unit

I was thinking on sliding a banged up prop on and trying to rotate, though I think it's time to flip it up side down and douse with penetrating oil, then I'll try that.

 

[Yesterday]

Re: War with lower unit

OK so update:
She is now standing on her head. The mid-section has been thoroughly bathed in penetrating oil focusing mainly on the drive shaft itself, but included everything. Hoisting up and down there appears to be a little better than 1/4" movement. Turning the prop-shaft does indeed spin the drive shaft and does NOT spin the crank/flywheel. The more tension I place upwards on the lower unit the harder the shaft is to spin do a degree but it's never brutal. After 20-30 minutes of up & down pressures on the LU and spinning the shaft however, there is no change. I thought I would let it sit and let the penetrating oil do it's thing.

Interim thoughts:
perhaps the shaft was at one point welded poorly and that's now having trouble coming out of the leg? I looked for signs of patches on the leg but don't see any. If a poor welded shaft is the culprit, I fail to see how it could have gone back in since the troubled area would have to be a few inches above the LU.

I scoured the web last night for pictures of legs (interior) to get some idea what the passage for the shaft looks like with some but not much success. I found some decent angle shots of a similar vintage 50HP and it looks like the shaft passes through a column but I can't see what sort of clearances there are, or know if that same thing even applies to an 850. There is a partition in the way of seeing the thruway from the power head side.

There was at some point, some heavy damage to the pivot/mount. I'm wondering if whenever that took place, there could have been something which bent the drive shaft? Seems unlikely, but then again that it's still "stuck" does as well.

At this point I'm grasping for straws, so any theories are more than welcome!

 

[Bosunsmate]

Re: War with lower unit

The passage is mostly as wide as a cars gear shift knob so no problems there. Where it gets tight is at the point where it closes in on the crankshaft mating coupling. This is in a part called an end cap.
I cant find a picture yet, but its basically a passage which is wider at the top where the crankshaft is and it tapers down to the bottom. So could well be the part holding on tight still.
To add some more musings. If you try and remove the powerhead and the driveshaft is still stuck there you wont be able to lift it either.
If you did damage the end of the end cap it wouldnt be too much of a problem.

 

[Bosunsmate]

Re: War with lower unit

Another idea is that you could undo the bolts on the water pump if you can reach them (you may need one of those spanners that are bent up then straighten again) but im pretty sure you should have enough room, then remove the prop carrier nut, remove the carrier bearing, then lastly remove the gear pinion nut.

If you did that you should be able to lift off this LU and leave the driveshaft behind and claim a partial success i suppose..
youd then be able to apply whatever directly onto the endcap down through the midsection.
As last resort youd then be able to lift the powerhead and get to the endcap. If you cut up the endcap to remove the driveshaft it can can be pulled out without splitting the crankcase.

Banged up prop and/or heavy damage to pivot mount says possible bent driveshaft to me.