2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

[cabovic216]

Model 90 ELPT SW S/N 1B114688
Having changed several water pumps before.... I embarked on trying to change this one, as we bought the boat a few months ago. After removing the 4 nuts that hold the lower unit (2 on each side), one more nut in front of the anodes, and the cotter key that holds the shift linkage (under the head).... I proceeded to yank the lower unit out.... but it won't budge.
After repeated attempts, I took a small sledge hammer and a block of wood and proceeded to try to pound it out 'carefully', no deal. I even hit it side to side to see if I could loosen it a bit... no go. Should I whack it harder ?
Eventhough the boat has low hours, it sat in saltwater (Half Moon Bay) for periods at a time. The engine looks like new, but I'm afraid I'm missing something.

Any ideas on how to dislodge the lower unit ? I like to do my own maintenance, so I ensure I know the condition of the surrounding components, and local boat shops just want me to 'bring it in' and let them do it.
Changing a water pump is a relatively easy procedure, and I hate to throw away $200.

Thanks in advance for any help.

 

[carholme]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

216;

Your engine comes up as a model:

1F90412DX MERCURY 2005 90

Parts listing:

http://www.crowleymarine.com/mercury-outboard/9983.cfm

Service Manual: P/N 90-858895R02

http://1manual.com/Mercury manuals/Service Manual PDFs/FourStroke/858895r1/cover.pdf

It sounds like you have all of the correct hardware undone and may have corrosion at the top of the driveshaft where it enters the crank.

Have you tried tapping wedges in each side to see if it will dislodge?

Gerry

 

[cabovic216]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

No, I don't think I can get a wedge in there of any kind, maybe a knife.... the opening is minimal in the front. I learned from a local boat shop that the solution to this might be to 'heat it', but he didn't say how to do it. Additionally he said it was a very delicate process, and of course, to bring it in.
I'm about ready to throw in the towel.... should I remove the propeller and heat the shaft a bit with a propane torch ? Or should the heat be applied somewhere else.
It seems that because the boat sat in salt water, there may be some corrosion at the top (this is what he said).
Any help would be again appreciated.... if it doesn't work, I'll bite the bullet.
Tx again

 

[cabovic216]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

I just tried 'wedging', and it opened a tiny bit, but still won't budge.... I believe the solution now is to 'heat it', but don't know where and how..... anybody ?
Thank you in advance

 

[Wingedwheel]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

I thought I read a thread on here the other day about the shift connector where the two shafts connect having to be backed off because it was threaded? Maybe I'm crazy but I thought I saw that. I'll look again.

 

[Wingedwheel]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

I found it... maybe its like this. http://www.youtube.com/watch?v=46RryAt1smY

 

[carholme]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

I have never been in a position to apply heat and don't know exactly how you would go about it to effectively get heat to the top of the d/s. It really needs to sit in PB Blaster for a few days but I imagine you are anxious to get going.

Maybe someone else will come in with a good idea.

Gerry

 

[Faztbullet]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

Here a old timers trick I have used before. Take a old damaged prop with bent blades and install it. Back down in the lake just enough to cover water intakes. Start engine and put in gear, slowly advance rpm till vibration shakes it off. Stand by with kill switch ready to pull when it falls off.

 

[carholme]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

If he had the threaded type of shift shaft connection, this would be visible externally.

Gerry

 

[sxmerc]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

There is no shift shaft connection to undo in this engine to remove the gearcase. The shift shaft is a splined connection, and will slide apart when the gearcase drops down. Call your Merc dealer, and order the five studs that thread into the driveshaft housing. (These mate up with the five nuts you removed.) Remove the two rectangular anodes at the back of the gearcase. You'll need to 10mm sockets to remove the bolt that holds them on. You will need an acetalene torch, and an air hammer from here. Where you removed the two zincs, you will need to heat the living crap out of the aluminum tab that the zincs sandwich on. This is the casting where the rear bolt mounts through. Also apply heat to the casting on the GEARCASE where the other four studs protrude down from. Once everything is good and hot, put an air hammer on the heads of all five studs, and give it hell. Between the expansion of the aluminum from the heat, and the vibration of the air hammer, you should start to see a bunch of crystalized salt start to fall from around all five studs. Try the same block and hammer technique you used earlier to get the gearcase to drop a bit. This process will probably have to be repeated several times to get it to come off completely. As your local mechanic previously stated, this is delicate work, and you will have to exercise patience and caution to avoid breaking everything. Once off, the studs will be rendered useless, as the airhammer has mushroomed the heads beyong repair. Replace the studs, remove all the salt from the stud passage ways with a rat tail file, and when you reassemble, grease the length of the studs liberally. I have done dozens of these, and haven't broken anything yet. You do of course realize that by making this statement, I've just cursed myself for the next one I do. Good luck.

 

[Antonioimp]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

I had the same problem and I use WD-40 overnight and hammer and 2x2 next day and I was able to devide the lower unit.

 

[cabovic216]

Re: 2005 Mercury 4 Stroke 90 Hp Model 90 ELPT SW - Lower Unit won't pull out

Thank you to all who helped..... in the end, I'm sorry to say that I threw in the towel.... I took it in to a local shop (Napa, California), and they ended up charging $240 for changing the impeller only. They said the lower unit required heating and lots of chemicals to free up.
What was disturbing was that after I paid them, they wouldn't even tell me how to take it apart ! They just said, bring it back in one to two years and we'll change it for you.
I DON"T THINK SO ! I bought the boat about 6 months ago, and although it had very few hours, it sat in salt water for long periods at a time (it was used for advertising).

Oh well, lesson learned - go to boat shops you're familiar with, or recommended by friends. I happened to be out of town and had planned to fish locally near Napa, so I didn't have many choices.

Again, THANK YOU to all.... this was my first post. GREAT WEBSITE !
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