Logo
FULL SITE MENU

Mercury 40 HP 1982, Lower Unit Stuck

J

jp_banks

Member
I have had this unit off a couple of times but this time it won't come off. Need to replace the water pump. I removed 4 bolts. The unit separates about 1/2 inch but won't go any further. JB has always been a great help to me. I hope he's still there and can help me once more. Thank you for any help.

JP
 
You are positive all bolts are out? Turn it upside down and try to spray some WD-40 or PB Blaster onto the shaft and let it soak overnight. After you do repairs make sure to lube the shaft splines sides only w/waterproof grease before reassy.
 
If it is coming down 1/2" then it is probably not stuck in the powerhead, but the shift shaft or water tube is hanging you up. Pull harder is all i can say. Look at the shift linkage to see if it is jammed or something. DO NOT HIT IT WITH ANYTHING.
 
I said I removed 4 bolts but actually I removed 5 (4 nuts and a bolt). The two nuts toward the front of the unit I cannot remove all the way because it won't drop down enough. Tomorrow I'll try the WD-40 or PB Blaster. By the way where do you find PB Blaster? I noticed someone mentioned the shift lever might be the problem. I don't remember taking anything else loose other than the nuts and bolt. The rod that connects the engine to keep it from raising out of the water on reverse, does it have to be removed or disconnected? I'll work on it tomorrow and post any success. Thank you and all the others who replied.

JP
 
Any good auto store sells it.

Spray the shifter shaft as well as the driveshaft.

Jeff

PS: Some get 'em off by running the motor--the vibration breaks the stuck parts free. You have to restrain the LU so it doesn't drop right off, however.
 
I have just about got everything disconnected so I can remove the engine and turn it upside down. I need to correct a statement I made about the clearance. I stated it was down about 1/2 inch. Well it only drops to 1/8 inch. I cannot see the shaft because the water pump cover looks like it is in the way. I guess I could guess at about where the shaft is and spray some PB-Blaster in that direction. Do you think that will work or do you have another suggestion? I have been working at this thing all day. It took me the longest to get the steering cable out of the tilt tube. But, I'm ready to lift the engine off the transom just as soon as my neighbor gets home. Any more suggestion will be greatly appreciated. Thank you.

JP
 
Put some spacers above the 2 nuts on the side and see if you can " use them as a jack " to force the lower unit down.-------Once you break the bond between the rust on the splines it may come off easily.
 
If none of that works, you can build a wood clamp system that clamps above the propeller shaft housing bell that you can hammer the lower unit off with. To do this take two 2x4's about 18" long and place above the round bell housing. bolt them together to sandwich the lower unit between them. Take two pieces of all thread about 2 feet or more long and drill holes thru the 2x4's that are clamped on and place a nut and water on one end. Then take 1 or more 18 inch 2x4's and put on the other end of the all thread with a nut and bolt. You will then have a clean surface to hit with a large hammer or sledge and one or two good hits and it will be off. this is a last resort as damage may be done. Normally you would never need to go this route and I would not recommend it if possible.
 
This last resort, is it better than drilling about a 5/8 inch hole high up the foot just below the bottom of the engine. Then I should be able to see the shaft and apply some lubricant (JB-Blaster). I can cover the hole later. Would you recommend that rather than the 2x4's? Let me hear what you think.

JP
 
just to double check, you have removed the nut in the front, the two nuts on the side are loose, but cannot be fully removed until it drops a little. You have removed the trim tab, you have removed the two nuts under the trim tab. I suppose you could drill a hole in the midsection and spray pb blaster in there. Either way is about the same. PB blaster is the more patient route.
 
I agree with the more patient route. As far as the nuts are concerned. There is no nut in the front, but there is a rod in front that comes out of the lower unit and connects to a mechanism that locks the engine when in reverse. I don't think that rod has to be removed. It has a nut on top of the rod and one at the bottom. If you think that rod is a factor let me know. I'll keep you posted.

JP
 
I got that unit confused with the 20 hp that has a nut in the front. How hard have you tried yanking on that lower unit. It sounds like you have removed the engine from the boat. Have you tried tipping it upside down and tried pushing and pulling as hard as you can? If it was still hooked up, I would try starting it and running it with all those nuts off to see if the vibration would rattle it loose like fastjeff suggested. You may be down to the old 2x4 method soon.
 
That rod is the reverse lock and does not come into play when you need to remove the lower unit.--No need to touch that rod.
 
After drilling two holes high up on the foot on both sides I sprayed lots of PB-Blaster on the shaft. I have it upside down in a wheelbarrow and letting it soak tonight. I've tried wedges, using a block of wood against the bullet, tried using a punch in top of the fly wheel while my neighbor pulled on it, but that was before I sprayed the lubricant on it. Tomorrow I'll probably put it back on the boat and try running it. If that doesn't work you might be right. I'll be down to the 2x4's. Thank you racerone for that piece of info concerning the reverse lock.

JP
 
Gear position does not matter for REMOVING the lower unit.------It can be in forward / reverse / nuetral or anywhere in between to remove the lower unit.
 
Well, I don't give up easily but this thing has worn me to a frazzle. I have tried everything but the 2x4's and I don't think I'm up to that. If after putting tremendous pressure using metal wedges and hammering on the shaft won't make it budge then I know the 2x4 won't help. It must be permanently fused together. I don't know how hard it would be to remove the engine, it being stuck on the shaft I would probably have the same problem. Unless someone have some alternative method, I think I'm just going to button it up and sell as is. Thank you

JP
 
Ok what I have done on these is to drill say a 3/8" diameter hole in the skeg ( in the proper place )---------Then I make an adapter for the crankshaft thread.------Then I hook the crankshaft end to a sturdy object.---Then install a short piece of chain to the skeg with a bolt.-------Use a hydraulic puller ( anchored to say a 4 * 4 truck ) to seperate the 2 items.-------It works too !
 
What do you mean by the proper place on the skeg, can you be a bit more specific? What are you calling the crankshaft? Is that above the flywheel? If it worked for you surely it will work for me. Just need to know exactly what you're talking about Thanks.

JP
 
Here is something I've noticed. When I lift the lower unit up and down as trying to pull it off, I had my Wife put her finger through the hole I drilled and feel the shaft, there was no movement of the shaft at all. Is this normal? It seems as thought there would be some movement of the shaft when lifting the lower unit up and down. Is there anything that could cause this problem?
 
It looks like you are pretty frustrated. if your wife did not feel any movement then the only movement your are getting is in the lower unit bearings. The drive shaft is definitely locked into the powerhead. If it were moving you would be done already. I like the idea racerone had about drilling a hole in the skegg. What he means (I think) is drill a hole in the fin below the driveshaft that won't cause a fluid leak but high enough the there is plenty of metal to prevent it from breaking. Make an adapter to hook on the the crankshaft above the flywheel, where the flywheel nut is currently. Hook it to fixed object such as a tree and cranky the other end with some sort of winch system. That should work if you can figure out a way to make an adapter to the crankshaft. I am still a fan of the 2x4 system as you can really knock it hard and get it to come loose. Never seen one that wouldn't come apart with that system. Good luck to you.
 
Thank you for your reply and for making things clearer. I have a feeling next week it's going to come apart. I'll be sure to let you know. Thanks again and have a great weekend.
 
Well, I made an adapter for the crankcase shaft, drilled a hole in the skeg. Put the engine between two trees and used my neighbors come along winch and he put so much pressure on it till it bent the handle of the come along and still nothing came loose. What would happen if I heat the shaft above the fly wheel? Is there anything around the shaft that could get too hot and maybe melt or cause a fire. I'm clean out of ideas. Do you think a strong electric winch or maybe a stronger mechanical winch might help? Anybody have any more ideas. Please let me hear them. I'm willing to try just about anything.

JP
 
Back
Top