Can't drop lower unit

[Laddies]

Re: Can't drop lower unit

Here's a link for the driveshaft hsg and gearcase
http://www.ishopmarine.com/ishop/js...cCatFilter=MM&eCatSupFldr=supplier-050-025-MM
http://www.ishopmarine.com/ishop/js...cCatFilter=MM&eCatSupFldr=supplier-050-025-MM

 

[xdays]

Re: Can't drop lower unit

Here's a link for the driveshaft hsg and gearcase
http://www.ishopmarine.com/ishop/js...cCatFilter=MM&eCatSupFldr=supplier-050-025-MM
http://www.ishopmarine.com/ishop/js...cCatFilter=MM&eCatSupFldr=supplier-050-025-MM

This is the same diagram I've been working from and as you can see it clearly shows 5 studs. As previously stated, there is also a pin at the front and rear of the case. Between the studs and the pins, it is impossible to place any twisting load on the LU, so it will only drop straight down. I have tied it to a tree and pulled with my truck, with no luck. I'm afraid to pull too hard, as I don't want to crack the case. Short of anything else, I'm at the end of the road and really don't have the money to have someone start cutting the case and drive shaft, etc..

 

[Texasmark]

Re: Can't drop lower unit

Mark, The Merc gearcases that you are looking at in the picture has 5 studs or bolts? I would not think Xdays should have that hard of a time removing it. It is pretty new, and corrosion should be minor.

The old Merc gearcases had three studs, the midsection had 2 studs, and there was one bolt from gearcase to midsection, under the zinc Anode. Is there any possibility that this is the issue?

Chris,

As I mentioned to him, my references are with respect to a 2 stroke. His is a 4. I asked him to tweak Merc and ensure that the lower unit design is the same for both powerheads. If not I could be blowing smoke.

When Merc redid the lower units, (going to guess '89) when the upper mid ranges went to 3 and 4 cyl from 4 and 6, they changed the bolt patterns from the earlier ones; possibly because folks had problems finding the last bolt, (under the trim tab) which also required repositioning the tab when finished and a lot of folks probably forget where it was so they had to go through the resetting ritual. With the new design they moved the bolt about an inch forward of the tab and it is clearly visible with the tab in place. The other 4 are clearly visible from the sides.

Mark

 

[blue90HP50]

Re: Can't drop lower unit

Xdays: I've been following this thread, I'm Not a technician, but here goes: I talked to my Merc Mech 2 days ago about your predicament. He said that if its a salt-water condition the shaft and socket have "grown together". You, or someone, mentioned drilling hole in side and cutting the shaft. That's what my mech said to do, too. However, my thoughts are to drill say a 1/2 inch hole at a location determined by you, close to horizontal to where the shaft and socket are located. A second hole may be needed close by for observation. Apply mapp gas heat to socket and shaft for 10- 15 seconds, then apply by spray a liberal amount of PB Blaster to shaft/socket. Let set for a day, see what happens. Repeating may be necessary. My 2 cents opinion, and I hope something works out. Blue

 

[Texasmark]

Re: Can't drop lower unit

Xdays: I've been following this thread, I'm Not a technician, but here goes: I talked to my Merc Mech 2 days ago about your predicament. He said that if its a salt-water condition the shaft and socket have "grown together". You, or someone, mentioned drilling hole in side and cutting the shaft. That's what my mech said to do, too. However, my thoughts are to drill say a 1/2 inch hole at a location determined by you, close to horizontal to where the shaft and socket are located. A second hole may be needed close by for observation. Apply mapp gas heat to socket and shaft for 10- 15 seconds, then apply by spray a liberal amount of PB Blaster to shaft/socket. Let set for a day, see what happens. Repeating may be necessary. My 2 cents opinion, and I hope something works out. Blue

Sounds like a great idea, but there are powerhead seals on the lower crank that have to be considered. I too read the thread response about cutting a hole in the side of the mid section and sawing the shaft in half, but what then? And where is the exhaust tube with respect to the shaft...if it has one? If it has one and it is around the shaft, you would have to cut through it too seems to me.

I still stick to my common sense guns here and reiterate what I have said more than once, that the SS shaft is lightly greased prior to assy at the factory and may be going into a bronze receiver at the bottom of the crank. Does not spell corrosion to me.

Additionally, if it were the shaft causing the problem, there should be at least a few thousandts of vertical movement in the shaft allowing you to crack the joint between the LU and MS, and one should still be able to raise the front or rear of the LU at least a few thousandts and crack it.

Really a weird problem.

Mark

 

[DuckOfDeath]

Re: Can't drop lower unit

Before I started drilling holes, I'd step up to a 5# sledge with a wood block. Hit it so hard it feels wrong.

 

[crem1]

Re: Can't drop lower unit

I don't know whether anybody suggested putting the gear in forward. If so, then we are back to square one. Deep Sea Foam anyone?

 

[xdays]

Re: Can't drop lower unit

Guys, I was out of town for the weekend and now the weather is pretty crappy, so looks like I'll be able to get to work on this LU tomorrow. I'm going to try to run the engine with the nuts backed off the studs to see if the heat and vibration will help it drop. I will post what happens. Thanks again for all the help in trying to resolve this frustrating issue.

 

[xdays]

Re: Can't drop lower unit

I give up, guys. I've tried everything that has been suggested, short of drilling into the engine, and I can't get that succker to budge.I am getting a strong flow of water from the pisser and the only reason I wanted to change the impeller was because I thought I should. I guess I'll just run it until I can figure something else out. Thanks again for all your help.

 

[sschefer]

Re: Can't drop lower unit

If you get to the point where you think you're going to cut it. Find a shop that does cryo freezing with liquid nitrogen. This is the new way to break the corrosion bond. When it's frozen the corrosion bond shatters and breaks up into small particles that are no longer bonding.

Gunk now makes a freeze penetrant that performs similarly. I just used it to remove some corrosion bonded bolts from a mid section and it worked when none of the other methods did.

The reason I recommend taking it to a machine shop is because if the corrosion bond doesn't let loose then they only need to freeze the shaft again and hit it with a cold chisle to break it. At the most you'll have a 1" hole in your mid to patch and off course you'll need to pull the power head and replace the drive shaft but that's minimal compared to other cutting methods.

 

[Chris1956]

Re: Can't drop lower unit

Can you disassemble the gearcase and remove the pinon nut? If so, you may be able to force the driveshaft to break the waterpump cover and pull out. It will then stay in the crank, and you can get to it.

I would check a manual. This will work on the older 2 cycle motors. You might check how to remove driveshaft from gearcase, for your model.

 

[Texasmark]

Re: Can't drop lower unit

You know, now that we have come this far, you apparently thought you "Had to do it" probably because someone told you that if you didn't change the impeller every six months the world would come to an end.................

When I was a teenager, my daddy bought a 10 hp Scottatwater engine. We had that engine for at least 10 years and the impeller was never changed....fished in salt and fresh water, salt brine and all that "stuff""""""""; churned up a lot of mud in Clear Lake, TX. and Taylor Lake, TX. beins they were so shallow that you didn't need a life vest when skiing. Just fall off and stand up in the mud.

I can't tell you how many times I ran that engine out of the water, with absolutely no water supplied to it for 5 to 10 minutes sitting on a rack in the garage or hanging on the fence at home. Like I said, never changed the impeller and never had an overheat problem. Only problem with that engine was one day I was running the San Jacinto River, below Lake Livingston, N. of Houston, TX. and ran across some old railroad pilings that someone cut off about 6" below the surface.....really made a mess......that is where I learned that 2 cycle engines use roller bearings on the crank-connecting rod interface.

So, what is all the fuss about nothing. Been boating since 1955 and NEVER had an impeller problem, salt, fresh, brackish, saline, mud, sand, you name it.

Current engine is a 2002 with the original impeller and it will pee 2" into the water at idle.

Gimme a break......sounds like the Al Gore fiasco.

And speaking of Al Gore, saw his 100' houseboat today ( I think courtesy of the NY Times or the WSJ) and the jet ski on the stern.....saw no windmills on it, nor any solar panels. I guess he powered all that with his CO2 breath exhalations, but wait a minute, CO2 is now classified as a hazardous gas......any vacancies on Mars? Gimme a break.

Mark and proud of it.

 

[xdays]

Re: Can't drop lower unit

Mark, I hear ya, man. I've been wasting more hours than I care to remember on this. I get a real strong stream of water from the pisser ( I wish I was so lucky! ) and have not had any cooling problems, so I'm just going to keep running it. Thanks again for all the suggestions.

 

[Texasmark]

Re: Can't drop lower unit

Mark, I hear ya, man. I've been wasting more hours than I care to remember on this. I get a real strong stream of water from the pisser ( I wish I was so lucky! ) and have not had any cooling problems, so I'm just going to keep running it. Thanks again for all the suggestions.

Ok man, hang tight dude....life is a "beach" and then you die. My hat goes off to senior citizens that can still have fun especially when you watch the AARP commercials and all such stuff. My problem is rationalization and it ruins a lot of things.....not everything, a lot of things.

Mark

 

[Antonioimp]

Re: Can't drop lower unit

Xdays,I have the same engine and I had the same problem last year to change the impeller.You must put the gear in forward ,use penetrating oil like you did and positionining a small piece of 2x4 in the front and use a very havy hammer at list 10 lbs and beng very hard.Is what I did and finally it separated.Antonio

 

[xdays]

Re: Can't drop lower unit

Ok man, hang tight dude....life is a "beach" and then you die. My hat goes off to senior citizens that can still have fun especially when you watch the AARP commercials and all such stuff. My problem is rationalization and it ruins a lot of things.....not everything, a lot of things.

Mark

 

[turtles11756]

Re: Can't drop lower unit

eventually you will have to get at the impeller. i have an old Johnson 18hp that sat in the garage for 27 years without starting. the original impeller was broken into pieces when i took it out .the motor would have run hot real quick and there goes a motor that never over heated in 52 years. if it's pumping water strong leave it but keep an eye on it

 

[JGra]

Re: Can't drop lower unit

Install a water pressure gauge on the dash. I put one on mine, I got tired of turning around all the time to make sure motor had a good stream. I have 3-5 psi at idle and 12-15 at full throttle.

 

[cloumar]

Re: Can't drop lower unit

Hi X,

This is strange what you have there ??? Last weekend I replaced the impeller on my Mercury 115-hp 4stroke 2007.

There are only 5 nuts to remove nothing else, but it was stiff to lower down. Myself I am a car tech so I am use to deal with hammer, prye bar and so.

I took a 2x4 and used it to bang it with a 3 pounds hammer - 2 shots each side few times and it finally came down about 1/8 enough to use a big screw driver and pry it gently for the rest. I was banging on the side right on where the the anti-ventilation plate starts with the body of the gear case.

Also if it is seized by corrosion you may use a good penetrating oil instead of WD40 - you could find some at any good autoparts.

Mario