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K. Kergan
K. Kergan, Marine Mechanic
Category: Boat
Satisfied Customers: 1030
Experience:  24 yrs exp. Inboard/Outboard mechanic Mercury/ Mercruiser, Volvo Penta and OMC, Johnson/Evin.
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Have 1986 Mercury 45Hp outboard. Can't get the lower unit

Customer Question

Have 1986 Mercury 45Hp outboard. Can't get the lower unit out. Model 0A915265. I have the two bolts by the prop out and the two nuts loose on the studs toward the front of the motor. I want to make sure nothing else is keeping it from dropping down etc.
Submitted: 10 months ago.
Category: Boat
Expert:  K. Kergan replied 10 months ago.

Hi, my name is Kerry

If you have it down 1/4" you must also have the nut on the front off?

Expert:  K. Kergan replied 10 months ago.

The driveshaft is likely stuck on the crankshaft splines.

Expert:  K. Kergan replied 10 months ago.

How long has it been since the leg was off?

Expert:  K. Kergan replied 10 months ago.

There are a total of 5 nuts, if you have them all off or loose and it won't come down, it's stuck on the splines.

Sometimes wedges work, be careful not to break the housing.

Customer: replied 10 months ago.
May have never been off. Water impeller needs to be changed. This motor was not used much for years until I got it. I put new stator coil ans ignition pack in and rebuilt carbs and have had about 4years of great service. I didn't know it needed to be broke down for lube etc. I have four nuts loose. Two by the prop and two on studs up on the sides.
Customer: replied 10 months ago.
wheres the fifth one?
Expert:  K. Kergan replied 10 months ago.

There in another one at the front, the stud faces upwards.

Expert:  K. Kergan replied 10 months ago.

Front center above the leg

Customer: replied 10 months ago.
when you say front,, you mean toward the boat?
Customer: replied 10 months ago.
how do you get to it?
Expert:  K. Kergan replied 10 months ago.

The stud is in the leg and goes through the exhaust housing.

Yes toward the boat

Expert:  K. Kergan replied 10 months ago.

It's not hard to get once you find it

Customer: replied 10 months ago.
by where that little steel rod goes down the the lower unit?
Expert:  K. Kergan replied 10 months ago.

It's about 1 1/2" above the top of the lower unit

Expert:  K. Kergan replied 10 months ago.

Yes

Customer: replied 10 months ago.
it requires a socket extension to go down that hole by the rod? sorry man, rookie here
Expert:  K. Kergan replied 10 months ago.

You can get it from the front with an open end wrench, you may need to tilt the motor up a bit if it isn't already tilted.

Expert:  K. Kergan replied 10 months ago.

I'll see if I can find you a diagram.

Customer: replied 10 months ago.
sorry man.. no bolt there, just solid housing. I have a book. It shows no other bolts. Doesnt mean there can't be though
Expert:  K. Kergan replied 10 months ago.

Just looked up a diagram, you are right, not the same motor I thought it was.

Expert:  K. Kergan replied 10 months ago.

Is the entire let down 1/4"

Expert:  K. Kergan replied 10 months ago.

leg down 1/4"?

Expert:  K. Kergan replied 10 months ago.

http://www.crowleymarine.com/mercury-outboard/275.cfm?mdl=SISONL

Expert:  K. Kergan replied 10 months ago.

http://www.crowleymarine.com/mercury-outboard/parts/275_170.cfm?mdl=SISONL

Expert:  K. Kergan replied 10 months ago.

It has to be stuck on the driveshaft splines

Customer: replied 10 months ago.
pretty much. I can rock and back and forth a bit, but seems like something about in the middle area of the lower unit holding it
Customer: replied 10 months ago.
wedges? wood? metal?
Expert:  K. Kergan replied 10 months ago.

The only possibilities there are the water tube and the driveshaft.

Yes wedges, either wood or metal

Customer: replied 10 months ago.
place close as I can to the middle of the unit I guess?
Customer: replied 10 months ago.
How much will it have to move before it releases? 2-3"?
Expert:  K. Kergan replied 10 months ago.

Be careful though, wedges can put on a lot of force

The middle might not be the best place, choose a spot where the housings are solid.

Expert:  K. Kergan replied 10 months ago.

The splines go in more than an inch but once you move it a little it will get easier

Customer: replied 10 months ago.
ok understand. well you have confirmed what everybody else has told me.. not too much solid housing to to work with it seems
Expert:  K. Kergan replied 10 months ago.

I usually go at the front and back

Expert:  K. Kergan replied 10 months ago.

Two wedges

Customer: replied 10 months ago.
understand. got it, will cut me some oak ones and let the wedging begin I guess
Expert:  K. Kergan replied 10 months ago.

If it doesn't break free easily, turn the engine with the wedges in tight.

Expert:  K. Kergan replied 10 months ago.

Start it for a sec with the wedges in

Customer: replied 10 months ago.
by hand or start it? I have it in forward gear.. got it. I had also heard that as well
Expert:  K. Kergan replied 10 months ago.

Good luck, I can be pretty difficult

Customer: replied 10 months ago.
thats what they tell me. patience i assume is the key?
Expert:  K. Kergan replied 10 months ago.

Yes, patience, don't break anything.

If wood doesn't work you may need to use metal, just carefully

Customer: replied 10 months ago.
Understand. Thanks for your help. Will see what happens. Not of much value at the moment, so the dice will be rolled!
Customer: replied 10 months ago.
Like log splitting wedges?
Expert:  K. Kergan replied 10 months ago.

Yes

Expert:  K. Kergan replied 10 months ago.

Or possibly a thin chisel

Customer: replied 10 months ago.
Got it. OK man. Appreciate your information and help. I think thats what I wanted to know. Thanks again.
Expert:  K. Kergan replied 10 months ago.

You're welcome

Expert:  K. Kergan replied 10 months ago.

Best luck and have a good summer

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