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can't get gearcase off mercury


jay the novice's Avatar
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06-12-04, 02:42 AM   #1  
jay the novice
can't get gearcase off mercury

Hi all you boaters out there.
Please be patient with me as i am new to this site and to boating.
We recently bought our first boat wich has a 50hp mercury with trim & tilt.
I think it's about 86 - 88 model 4cyl 2 stroke.
Can anyone help me as i am in the middle of taking the gearcasing off,i've undone all the bolts down below but it only moves about 5mm apart.
Have i missed something out or could it just be corroded ? Just spent the last three hours looking for something obvious and now have headache (aaarrgh!)
Any help would be much appreciated.

 
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06-12-04, 07:38 AM   #2  
in most cases of this type it is that the spline shaft is
frozen into the crankshaft. if it hasnt been removed for many
years a lack of grease and the resulting corrosion cause them to
bind. It will take a bit of force but you should be able to remove the
lower unit. Double check thqat all the bolts are out and drive a wedge
in there. dont forget the safety glasses.

 
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06-12-04, 04:14 PM   #3  
jay the novice
boatmech

Hi boatmech , Thanks for your advice but i still can't get the dam thing off, i can only see four bolts that hold it all together, is there any shaft nuts or something that should be undone? This thing is jammed solid.Many thanks again.

 
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06-12-04, 11:58 PM   #4  
jay the novice
boatmech

Thanks for your advice mate,but still no joy, i've just spent the last 8 hours trying to get the dam thing off with no joy.This thing is really jammed on.(or have i missed something?).It moves freely up & down about 5mm but sounds too metal like to be corroded,I thought just the four bolts would be it and hey presto??????

 
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06-13-04, 07:20 AM   #5  
Hello: Jay

I merged your two questions into one question. Doing so makes it much easier to follow along in the process of providing additional help to the original question. Kindly use the reply button each time additional questions are asked on this same problem. Thanks.

If the lower end had water in the gear case, a part may be rusted. The rust causes the metal to become swollen slightly. That slight swelling may be causing the binding, providing all bolts and screws, etc are removed.

If that is the case, BoatMech is correct. You will need to use a wooden wedge between the case and the bottom end of the engine. Do this slowly a bit at a time.

First, hit the wedge in some to apply pressure downwards. Than remove the wedge and push upwards. Repeat using the wedge. Than repeat pushing upwards, bit at a time downwards than upwards. You'll be working the lower case down some than up some little bit at a time.

Hopefully, the up and down motions and forces will work the two or more binding internal parts to break free.

You did not mention if there was water in the lower case or any prior evidence of any water in the case. Which would lead to knowing why the case is so difficult to remove. Nor any mentioning of what parts where already removed prior to the difficulty of removing the lower case.

Based on the current difficulties, something is not removed or the lower end was not running or moving freely prior to your attempts to remove the case. Lots of possibilities but not much details provided.

Kindly post why you are removing the case? Was the gearing frozen prior. Prop not turning? More prior details may help lead to an answer why the case is so difficult to remove.

Sharp Advice. Life Long Boating, Fishing and Navigation Enthusiast. Web Site Host, Forums Monitor & Multiple Topics Moderator.

 
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06-13-04, 03:33 PM   #6  
jay the novice
Sharp Advice

Please accept my appologies for not using this site properly, didn't know how to reply in the proper manner Thanks.
Like i say this is the first boat i've owned and when we bought it it had been out of water for a few months so i thought best check the water pump etc before we use it.I drained the gear oil to my horror found nothing but a white sludgy mess oozing out, so decided it was time to investigate.(obviously water had got in at some point).looking at the service book there are just four retaining bolts to remove and the whole unit should just slide out with prop and everything in tact.Is this the case? or have i overlooked something?
Many Many thanks for your knowledge.
Jay..

 
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06-13-04, 08:46 PM   #7  
Hi: Jay

Now that we know water had gotten into the case, the possibility of rusting resulted. Most likely prying the case down is required. The exhaust system and drive shaft are most likely rusted and causing the binding.

May be a good idea, at this point, since more internal damage may be found, to remove the prop and all it's internal gearing before attempting the cover removal using the wedge on the case to force it apart. Prop and gearing removal first would likely make the case seperation process easier & quicker.

Plan on the need for additional work and additional parts required for a complete repair once the case is removed. Water in the lower end left inside for an extended period of time, is likely to have damaged several other parts.

Try removing the prop assembly first. Than use the wedge to seperate the case from the engine.

No apologies needed for double posting two questions. Using the reply button simply helps to keep the thread going, so others can follow along and post helpful advice, if they have ideas to help out.

By The Way: (BTW)
BOAT stands for:
Bail Out Another Thousand...B.O.A.T.

 
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06-13-04, 11:24 PM   #8  
jay the novice
Getting no where fast!

Hi once again Sharp.

Been out there today taking the prop and gearing out.Boy that was a struggle, again everything was corroded and i ended up emptying a whole can of WD40 in there and warming the casing slighty before anything would shift...
I keep trying with the wedge but this unit seems stuck forever.The exhaust seems to be free as the 5mm gap i have is just enough to see.Also pushing up and down from this point is easy but then it comes to an abrupt halt on the downward motion sounding like there is some sort of pin or something stopping it..
Leveridge from one end to the other,or side to side points directly to no movement in line with the shaft if you know what i mean .
I even managed to undo the nut that is inside the prop tunnel holding what i assume would be the pinion gear to the drive shaft thinking the case would come off leaving everything else exposed ..That hasn't worked either.
Really hope you could come up with some sort of solution for me mate as my MAGIC WAND seems to have run out of batteries!!!!
THANKS once again.

Jay

 
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06-14-04, 07:18 AM   #9  
Hi: Jay

I too, have just about totally run out of ideas and suggestions. My own logical "Thinking Cap" has also run low of battery power. Seems you have tried just about everything possible to no avail. Yet something exists that causes the problem to remain.

Based upon that premise, there comes a time when the do it yourself person needs to seek professional advice or the help of a professional. Therefore, it may be wise to visit the local boat repair shop where you intend to purchase the needed parts.

Since you would be a parts purchasing customer of that selected boat repair shop, it would be wise for the owner and or shop mechanic to advise you how to remove the lower end cover under the conditions presently encountered.

Providing you with the information needed how they would accomplish the task, is in their best interests as well as yours. If they do and will provide such. If not, find another shop that will. Than you have found a friend in the business. A WIN - WIN for both you and the shop.

All else fails, have the shop do that part of the work. Than purchase the needed and or suggested parts and reassemble the lower end yourself. Doing so will end the current headaches, save a few bucks in the process and be a good learning experience for the next time you need to remove the lower end case.

Whichever will work best for you at this time. Once the case is removed, use the reply button to update this thread (post) with full details as to what you did or the shop did to get the case removed. What was causing the problem and how the entire project turned out.

Doing so, you will be helping other boat owners whom are also reading this thread. Sharing we all learn more. I'll be gone from here for the next few days. Not able to post back additional replies. I will check back upon arrival.

Hope by than you figure out a means to get the case removed and read your update to this dilemma. Provide full, specific and complete details when you do accomplish the task. Other readers will learn more too....

Regards & Good Luck Jay
Sharp Advice. Life Long Boating, Fishing and Navigation Enthusiast. Web Site Host, Forums Monitor & Multiple Topics Moderator.

 
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06-15-04, 03:49 AM   #10  
jay the novice
At Last !!!!!!!!!!!!!!

Hi again Sharp.
Trial,error And Patience must be the key.
After spending a whole entire weekend shut in the garage on what would assumingly be an easy task certainly took its toll on my patience (not to mention the wife and kids )so decided enough was enough,no point loosing too much sleep over a boat.
The next day i got in touch with my local boat repairer and said i need to buy some parts from you but have a slight problem.(like you say if your gonna spend money with them its in their own interest to help).He suggested the same as Boatmech and use a wedge or worst case scenario cut a hole in the mid section and cut the drive shaft.Option two didn't really appeal to me too much so off i went ready for another night in the garage.
prepared for the worst and gas axe nearly at the ready, decided to have one more go with the wedge..
This time Tapped one at the front,one in the middle and one at the end hitting each one in succession pretty dam hard and thinking to myself , i really dont want to cut any holes.All of a sudden PLOP out it came (good job my foot was underneath otherwise could of damaged the fin at the bottom).
RELIEF RELIEF RELIEF!!!
I must say though i think soaking the whole unit for nearly three days with penetrating oil must have helped.Everywhere i could find a hole or crevice out came the squirty can,even to the stage of undoing all the bolts that hold the engine to the mid section and just lifting it up that 5mm backlash that you have and SQUIRT SQUIRT SQUIRT anythings better than nothing.
I really hope no one gets this problem like i did as it should never really occur if the motors been looked after and regularly serviced, so i'm told.
Thanks for all your help guys, will keep you posted on anything else that might be of interest (i'm sure there will be lots ) SO GLAD I FOUND THIS SITE>

Jay

 
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06-15-04, 06:55 AM   #11  
good job, thanks for the feed back.
now check the splines very closely for excessive wear.
they have been running dry and rusty for a while.
Look up the exhaust and spray some penetrant in the end of the
crank. clean up the driveshaft and apply some good moly lube
on reassembly.

 
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06-20-04, 11:04 PM   #12  
jay the novice
The jobs gettin bigger

Thanks Boatmech,
Checked the splines at the crank end , and yes as you propabably guessed by now not much of them left.Also some guy has had a good go at it all before me as the driveshaft has been cut and rewelded.
Besides all of that theres more drama .................
Me being nosey and all that, i decided to have a look at everything else seeing as i have the motor out.
Gear end seems to be fine (no scoring,broken teeth etc.)but the engine block and head cover are so badly corroded somebody thought they would fill em up witth body filler and throw a bit of black paint over the top.I now look forward to more nights in the garage doing a complete engine rebuild.
The good thing is at least i'm getting to learn all about boat engines and the way they work . (makes a change from doing cars.)
Keep you posted guys..
Jay

 
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