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2001 Mercury 150HP DFI stuck lower unit

J

jggon

New member
Really need some help here. Seized engine that need to repair, I have it hanging from the crane for 3 days now, all 10 nuts that put together powerhead and lower unit are out, tried soft hammer pry bar every day for about 1 hour but the lower unit does not separate. The only thing that comes to my mind now is to insert the lifting eye in the ball of my son truck and tie the lower unit to my truck and both pull at the same time (crazy?).
 
Are you able to get the pry bar between the lower unit and the intermediate housing? (BTW, Not the way to remove a lower) If yes, chances are the splines of the input shaft are rusted into the crank shaft splines.
 
Hi, thanks for your reply, I apply the pry bar between the driveshaft housing plate assembly and each of the 6 studs one by one it does not move at all. The Gear housing is completelly out.
 
Be specific with your terms.--------------Are you trying to seperate the lower unit ( gearcase ) from the exhaust housing or are you trying to seperate the engine itself from the exhaust housing.
 
How about you take a picture of what you have. I don't understand if you have the lower unit removed or not, or are you just trying to remove the power head from the exhaust/intermediate housing.....
 
Thanks for reply, yes lower unit is out already, I'm just trying to take apart the powerhead from the exhaust housing.
 
What happens here is that water may have leaked in between the stud and the exhaust housing.---------This then results in corrosion and corrosion products pack tightly in the clearance space.Very tight in fact !-------------So try to see which studs will turn using a thin pair of double jam nuts on them.-----------One or two studs may be jammed and you need to identify them.-------You then may have to use some heat on those.
 
Was it properly recovered or left to sit with water inside the engine ??--------------It may all be worthless due to corrosion on precision parts.
 
Previous owner said he flush it and run it for 20 minutes before he stored under roof. But he took the spark plugs out.
For what I can see after taking out the cilinder head and the air handle there is no much corrosion, the rest of the engine looks like new.
Can't tell about the computer and other electrical components until un-seized.
 
Get a can of PB Blaster and hit every nut, bolt and stud several times a day for a week. Tap on them lightly while spraying it.
 
If PB blaster dosen't work after a week , you will have to heat the exhaust housing around the studs, and place nuts on them, and use a dead blow hammer to try to move the SOBs. Oxadised alumium and bolt threads have a tendancy to weld themselves together sort of. Try the double nut methade first before using heat. Are you sure all the bolts and nuts have been losened or removed?
Best of Luck Oldman570
 
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Applied one of those Home Depot torch on the studs and over the gasket for about 30 minutes, laydown the motor over wood on the upper powerhead and the bottom of the exhaust so everything else is on the air, step over the section where both merge and jumped several times, nothing. I will try to move the studs before trying anything else. I did it last night before reading your reply this morning.
All the 10 nuts are removed, I'm doing it using the Mercury service manual, but I was able to move only 1 stud the others are like welded.
 
Drill a small hole from the side into the exhaust housing ( near the top ) till you get to the stud.-----------Now add some penetrating oil vial that small hole.-----------If it still holds on then you can drill it bigger to " cut " the stud , that should do it.
 
Are you sure this engine is worth repairing?

You may need to use the welding rod/8d battery trick. You double nut the studs, ground the engine to a 8d battery with a jumper cable lead, insert a weld rod in the other jumper cable lead and hook it to the positive of the battery and hold the rod tight against the nuts until the rod starts to smoke. (This will heat up the stud completely) Now grab a wrench and loosen the stud.

This method works well.
 
I think it is worth, there is almost no wear on the cylinders, probably the only thing to replace are the upper and lower bearing and the rings.
Is either that or buy a new outboard.
The battery trick make sense, I may use the 2 batteries on the boat after a full charge.
 
Thanks to all for your help, I used all the sugestions and finally got 7 studs out, the other 3 I had to cut with a dremmel 1/2' on the exhaust section.
 
Glad to hear that you finely got it apart. You want to make sure to use good flat washers, on those studs that had to be cut, when you put it back together. I would also put some red silicon (heat resistant) sealer on all the studs also to help keep the corrossion from happening again.
Oldman570
 
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