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35 Merc Lower Unit Removal

"Not Good! At first it seemed

"Not Good! At first it seemed that the "walking out" method was working but it wasn't. The shims I used ended up deforming the lower unit because of too much pressure. I'm giving up on it and am going to put the saw to it in the next day or so. But I have a couple of questions:
I'm not sure what size motor I have....I don't think it's a shor shaft but where do I measure from? I'd like to pick up a new lower unit but want to be sure I have the right size/year for my motor. Will different engine sizes fit my 35? In other words, do I have to look for a 35 lower unit or will a 25, 30 or 40HP lower unit also fit? I have an '86 35HP."
 
"I know the 35s and the 40 are

"I know the 35s and the 40 are the same from late 70 to late 80s. In 84 they started making the 4 cyl 40hp, thats when they called your engine a 35 instead of 40. They also changed the shape of the gear box, but the old style should fit. Don't buy anything yet, you still need to get the shaft out and check the ctankshaft splines. These engines are know for loosing the lower seal and bearing. This washes the lube off the shaft and you know the rest."
 
"JB, Thansk for the heads up o

"JB, Thansk for the heads up on the lower unit, I'll hold off on buying one for a while. But after I cut off the lower unit, will the lower housing of the motor (the part that houses the rest of the shaft and the exhaust housing) come off once I get the nuts off where it looks like it attaches under the head? I'm just wondering what I'm in for...."
 
"I don't see any reason to

"I don't see any reason to remove the powerhead from the exhaust housing. I would think you could wiggle the drive shaft, tap the drive shaft inward, or put a slide hammer on the shaft to remove it. The only reason for removal would be for overhaul of the engine. If you want to remove the power head, then yes remove all the lower nuts under the lower cover, remove flywheel and flip all the electronics fwd, no need to disconnect them just remove the fwd and aft mounting brackets. The powerhead will be stuck to the base, some additional force will be required. Its a pain to clean the gasket surface on the base plate, exhaust housing, and powerhead. I would skip this step if you don't need to. Look here if you want to look at parts diagram.
http://www.usboatsupply.com/Mercury_Mercruiser_Parts_Catalog3a.php?mc=01.
http://www.themarinedoctor.com/cgi-bin//YaBB.pl?num=1175964588
for transom length

Edit, I need a piston for my parts engine if things go bad, haha"
 
"JB, I cut the lower unit off

"JB, I cut the lower unit off last night. To my surprise I don't see any rust where the shaft enters the powerhead. But that shaft is pretty solid......now what? I'm going to pick up a slide hammer on my way home from work but I'm not sure how this is going to work.....will I need to drill a hole in the side of the shaft to attach it? Or will I need to get a piece welded to the shaft?"
 
"tap on it with a hammer, at t

"tap on it with a hammer, at the top of the shaft there is a spring loaded pin to preload the drive shaft, thus allowing a little free play inside the crank splines. It would be best if the top of the crankshaft was against something solid to avoid the crank, bearing, and flywheel from damage. Couple of taps and then the slide hammer, anyway you can attach it."
 
Make sure you post some pics o

Make sure you post some pics of the aftermath Andy i'm really curious to see as to what has caused this problem. Cheers.
 
"years of neglect, thats why w

"years of neglect, thats why we say every other year on the water pump, not till it fails"
 
"Yes, it's amazing what a

"Yes, it's amazing what a 50 cent tube of Moly Lube will prevent - besides, what fun is an outboard if you don't occassionally tear it down
"
 
"I'll surely post once I g

"I'll surely post once I get it apart but it's not looking too good right now. I cut off the lower unit and it is the drive shaft that is stuck. I lubed it up good with Kroil someone mentioned.....I also drilled a hole through the shaft about a 3/16" hole to which I fed a piece of steal cable through and clamped it to make a loop....to this loop I attached the come-along and hung it from the ceiling. I'm also able to attach a slide hammer but it's not helping much. So basically, the eninge is hanging in my basement by the shaft only.....and I've wedged a 2x4 between the motor housing and the come-along for more pressure.....but nothing yet, it's only been about 24 hours. I'll try to post a photo soon."
 
"when you use the slide hammer

"when you use the slide hammer it needs to be attached firmly, the cable allows too much flex and give. I would beg borrow or steal a air hammer/rivet gun, put a bolt into the shaft and bang it out. Those big air chissel/hammers really pack a quick punch."
 
"Yeah, I figured there would b

"Yeah, I figured there would be too much give in the cable.....before I search for the air hammer, I had another idea.....I'm going to try putting a piece of 1" BLACK pipe over the shaft, then putting a bolt in the hole.....and using the pipe as a hammer, so rather than pulling on the shaft, I'll be "pushing" it off....but thanks for the heads up on the hammer. Stay tuned.....the saga continues."
 
"Okay, no luck with black pipe

"Okay, no luck with black pipe too tight inside the housing. Made a bridge out of angle iron and put a shackle on the shaft, pulled it with a muffler type clamp...deformed the shackle and the clamp but was able to put quite a bit of force on the shaft. Finally, put a hose to the intake pipe and started the motor.....let it run for quite a while, that shaft bounced around a little in there but didn't shake free. So, I re-installed my clamp/bridge. Motor runs Great! I'd hate to say it's over...... Question: Am I out of options? What do I do next? Spring is here!
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"
 
"Andy, I feel your pain as I h

"Andy, I feel your pain as I have the same issue with a 1986 Merc 35 outboard (serial A951897). Right now, I have the motor upside down saturating the drive shaft with PB Blaster. The emails on your motor have been helpful. I also disconnected the shift shaft coupler (under the carb) thinking that may help but no luck yet. We are still stuck tight. Mayber if we get one more, we could start a club? Did you price a lower unit yet? This motor is actually my neighbors and I am trying to help and keep the cost down. Thanks...Stubborn Tony"
 
"Hey Stubborn Tony, I thought

"Hey Stubborn Tony, I thought my link was dead. Sorry to hear you have the same issue, this stinks, usually it's a problem with getting the motor to start....not this time. I've got a good motor but it's useless. I'm going to try an impact hammer first, then as Brent says, I'm going to remove the powerhead try to remove it using heat or something. Hopefully Graham Lamb or JB have more suggestions....we'll see. Good luck with yours and let me know how you do."
 
"I'll keep you posted. Ju

"I'll keep you posted. Just tried banging it again (hammer/wooden block against cavitation plate) after it sat upside down for a few days in a PB Blaster bath. No luck. I have to go out of town for a few days, so I will flip it back over and re-dose the drive shaft with Blaster, and deal with it again when I am back in pocket. If we could get directly to the drive shaft and coupling...I think a combo of dry/ice, then heat might help break the bond? I appreciate the feedback and comments from all.
Tony"
 
"Andy i think if you remove th

"Andy i think if you remove the power head you will see the drive shaft at the entry point to the bottom of the crank. Got any mates with an oxy acetaline kit? some extreme heat to the drive shaft as it enters the crank should be enough to either melt burn any rust etc. or even expand the seized part enough to belt it off.

Remember you have already cut off the lower or did you actually CUT IT OFF AT THE MIDSECTION?? unit, remove the cover around the bottom of the cowling undo the (i think 6 or 8 )nuts and the top should separate from the midsection taking the remainder of the drive shaft with it. the midsection gaskets are replacable mind you I just made my own from ACL Gasket paper and they work a treat. Keep us posted !!"
 
"Tony, heat would probably bre

"Tony, heat would probably break the bond but just getting to it is the issue, especially if the lower unit is still attached.

Brent, Yes I did cut the lower unit off, right through the drive shaft at the water pump. I don't know how I'll remove the nuts that hold the housing at the cowling, the nuts are rusted and impossible to get an extractor on, there isn't any room. I purchased an air hammer last night so now I'm working on rigging up a system of connecting it to the drive shaft so I can try hammering it off. I'll let you know how I make out but I'm not to optomistic at this point. I may have to resort to taking the powerhead off somehow."
 
"NO LUCK <[img]"http://www.mar

"NO LUCK
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with the air hammer. I gave up after about twenty minutes of hammering away at the shaft. Looks like plan "B"; remove the powerhead. Unless anyone has any more suggestions......
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Come on, give me your
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"
 
"You know what else crossed my

"You know what else crossed my mind? What if I somehow created a joint between the end of the drive shaft and a modified lower unit? In other words, creat a universal joint on the end of the drive shaft with a mating end on the lower unit with a cut drive shaft......and just leave the seized drive shaft in place.....at least I'd have a motor to use. Right now all I have is exhaust pressure as propuslion."
 
"Andy, a joint already exists.

"Andy, a joint already exists. If you install an extension kit on a (normal) motor to extend the shaft from short to long, a stub shaft simply inserts into the end of the existing shaft to make up the extra 5 inches.

I am unaware of anyone who has had the end of a "stuck shaft" machined to allow something such as that, but it may be possible (?????)"
 
Use the air hammer to hack off

Use the air hammer to hack off the nuts holding the power head on the midsection. (as they are all rusted you said)Once you got it off you should be able to get a better look at it. obviously belting it down away from the engine is not working so once off try belting it side ways both ways inwards outwards everyway possible. Dont be scared to give it a hrad time as the shaft is useless to you anyway.h
 
"Graham, That's interestin

"Graham, That's interesting about the extension.....so, why wouldn't Outboards be designed with a separate shaft from the powerhead to the lower unit? Seems like it would save money in the long run.....they could stock two shaft lengths and make one lower unit without a long shaft sticking out of it which would save on shipping those larger crates.....I know balance may be an issue but....

Thanks Brent, I've never owned an air hammer before so I'm a little inexperenced at what can be done with one. I'll give it a shot and let you know."
 
"save the air hammer for now.

"save the air hammer for now. post a pic of what nuts you are talking about.
Did you try to hammer the drive shaft in towards the powerhead, then slide hammer it out? Try forcing the drive shaft CCW with vise grip and hammer? Time to start a new thread"
 
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