Before I break something, Lower unit removal Evin. 85hp 1975

matthysone

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Lower unit will not separate on my Evinrude 1975 85hp!

I'm confident I've removed everything: Shift shaft in the head; 4 bolts with 9/16 head; trim tab and hidden bolt; 1 bolt with 5/8 head. Sucker will barely drop, can rock it to get a sliver of daylight. I've applied as much persuasion as I dare tapping in flat screwdrivers and then tapping through a block of wood. Just got the boat don't know if its ever been separated.

What am I missing? Does the shift have to be in a certain position? Exhaust or water piping seized?

Going on vacation with it in a week and it needs a new pump.

Thanks.

This is a pic of what I'd like to get to:

 
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crb478

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

When you say shift shaft are you refering to the one under the carbs connected to the bellcrank? Have you tried turning the powerhead by the flywheel to see if the drive shaft may be tight? Can you put it in geat and rock it againts the motor? I can not remember how many bolts are in there, but it sounds like you have them all. I just remember it is one more than it seem like it should be.
 

ezeke

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

Be sure that the pin is really out of the top of the shift rod - click the thumbnail below.

If the shiftrod is loose, take the spark plugs out and have someone turn the flywheel while you gently rock the gearcase from side to side and forward to back; it may break the rust or hydraulic lock on the driveshaft.
 

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matthysone

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

Thanks for the replies.

Yes the shift shaft is disconnected via removing the bolt that acts as the fulcrum and spreading the forks.

Can you put it in geat and rock it againts the motor?

Not quite sure what you mean here about rocking it against the motor.

I have not tried removing the plugs and turning the fly wheel yet but will try that after work. Should it be in gear while doing this?

It is really tight but I can get the lower unit to rock ever so slightly back to front.

Thanks
 

ezeke

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

It does not matter if it is in gear, but turning the flyweel will be easier in neutral. The driveshaft on your motor is always engaged with the engine when the gearcase is in place.

Have some support on the gearcase; if it breaks free it will fall hard.
 

matthysone

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

Update. I'm working 13hr shifts this weekend so haven't had time to rock the fly wheel, however, here's an observation:

I put the LU in a tub of water but only an inch or two above the water intake; I pulled off the water outlet hoses off the heads; started engine and no water from head outlet; put a hose with cone tip into head water outlet and turned on water; removed the hose and then the water pump works fine.

As I just got this boat, I've only tested it with earmuffs and the above tub with no water output from the pump. I'm wondering when I test it in the lake if the higher water level will help prime the pump as my hose did.

Just some observations about the water pump I thought I'd share. I know my major obstacle ahead is freeing the spline shaft from the case above.
 

DrJRiddle

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

I just removed the lower unit on my 1976 85HP Johnson. I had 6 bolts holding the unit in place, not including the one I had to remove that only held the trim tab. 7 bolts removed in all. Disconnected the shift linkage and it dropped right out.
 

wilde1j

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Apr 15, 2002
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5,964
Re: Before I break something, Lower unit removal Evin. 85hp 1975

Drive shaft splines might be rusted into the crankshaft bottom. If so, it will take some persuasion to free up. As Ezeke suggested, put several LU bolts in at least a few turns, BC that sucker will fall hard when it break free. When re-assembling, make sure to use the moly grease on the splines and use the O ring if the top of the driveshaft has an O ring groove.
 

matthysone

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

Well, I shook the flywheel and lower unit at the same time with no luck.

I definitely have all the bolts out and the shift shaft disconnected so it's definitely the splines. It's scary applying that much persuasion due to the aluminum casting.

Tomorrow I will be persuasive if not down right mean! Anybody have any suggestions? Wood shims? Screw driver? Big rubber maul?

Thanks
 

ezeke

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

If you use wood shims, work them in front and back in such a way as to keep the gearcase from being pulled at an even angle from the midsection. Keep turning the flywheel while applying the wedges as much as you can. Shaking the flywheel does nothing, but turning it clockwise forces the driveshaft to move inside the crank.
 

matthysone

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

At the same time I'm adding pressure to the spline joint there will be equal pressure at the lower end of the drive shaft. Where is the equal amount of pressure being applied exactly and is there a chance of damaging something below if the spline refuses to come apart?

Thanks for the input.
 

ezeke

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

The drive shaft ends at the pinion gear which has a connector.

The driveshaft is currently locked by either rust from not being lubricated or by hydraulic lock from too much lubrication. Either will be difficult to break.

If it were my job, I would put the gearcase back in place, put the four side bolts back in loosely and run the motor in neutral in a barrel of water while pushing the gearcase back and forth and side to side: this will usually break the bond if it is rust, which is most likely. There is one other possibility which is that the the splines are worn and that the driveshaft has turned and locked in the crankshaft.

The extreme repair is to cut the driveshaft and rebuild, so nothing that we are discussing here is extreme.
 

wilde1j

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

I've used the wedge idea Ezeke mentioned with some success. I used two or three oak wedges and progressively drove them to keep the LU square to the midsection. You'll be gaining very little in the beginning, typically 64's of an inch, then bang and the LU will drop free. BTW, as Ezeke points out, at this point, nothing's drastic, BC if you can't get the LU off, it can never be serviced again EVER!
 

matthysone

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

Update. My water pump is working fine now after some back flushing. I still need to get the lower unit separated but am putting that task on hold till the end of the season or at least till after our vacation. So the pressure is off to get it done now and glad I'm aware of the problem before the pump officially is dead. I do appreciate the help offered and will use that advice soon.

I'm off to sail Okoboji.
 

matthysone

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

Here is an update of success. I finally got the unit separated with a sledge hammer and a block of wood. In the pic is where I placed the wood block on the lower unit. After several hard whacks I alternated sides. It was slow going but ever so slightly the gap increased until finally it fell free. I only had it 4 inches above the ground so it didn't fall to far. I went through several 2x4's before this block of wood. The 2x4's shattered to give an idea of how hard I hit it. Thanks for your helpful ideas. Now I'm on to my next problem: LU stuck in reverse but that's in another post.

Hope this gives some encouragement to those struggling to separate their lower unit. I didn't exactly find rust in the splines, more of a black crusty build up.

PepinLakeMNSept2009.jpg
 

pearljameast

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Re: Before I break something, Lower unit removal Evin. 85hp 1975

Be sure that the pin is really out of the top of the shift rod - click the thumbnail below.


I know this is an old thread, but I have been looking thru a number of these just trying to get a picture of what it is that I need to disconnect/pin remove with the shift linkage and all the posts are too old and the links are expired.

Please help, otherwise I'm winging it tomorrow

P.S. I also have a '76 evinrude 85hp

Thanks
 
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