1985 Mercury 60 hp lower unit removal

[drtyjers]

Hello All -

I just purchased a 1985 60 hp 3 cylinder Mercury with manual tilt and no oil injection. I am in the process of pulling the lower unti and replacing with a jet unit. I removed the 4 bolts as instructed and the lower only dropped abiout 1/2 inch. I am not able to determine if I need to unbolt the shift shaft or if it is splined and simply slides out?

If the shift shaft is not holding the lower on, what is the best method of seperating? I've heard wooden wedge block, just wacking the lower, using straps to seperate?

Thanks in advance!

Jake

 

[oldman570]

Re: 1985 Mercury 60 hp lower unit removal

Your motor should have a splined shift shaft and could have some coression on the driveshaft and shift shaft. Never hit the LU cav plate as they break easy. Wooden wedges might pop it loose but only use them in a area where the casings are thick and well constructed around bolt holes. You can hang it from the LU to a tree or motor lift and use PB Blaster shot thru the opening on the shafts with the motor only a inch off the ground and see if it will run down the shafts and help free the LU. JMO
Oldman570

 

[Texasmark]

Re: 1985 Mercury 60 hp lower unit removal

When you invert it, put it a couple of inches off the floor so that when it falls it won't hurt anything and a rope around the bottom of the midsection will catch it from falling over. A board or other softer than concrete insert would certainly be in order.

Mark

 

[drtyjers]

Re: 1985 Mercury 60 hp lower unit removal

Well I used pb blaster and had it inverted for an hour then strapped the lower and upper to try to pull it apart. I'm using 10000 pound straps and it will not budge. I guess I'll hang it overnight and see if that makes a difference.

Any other suggestions?

Thanks.

 

[Texasmark]

Re: 1985 Mercury 60 hp lower unit removal

Yes. Since you have half an inch of clearance and the toughest part of the casting is around the interface with the mid section, you might drive some wedges (wood, plastic like you use for cutting trees down) driven in each side of the interface area where the studs are located. I'd drive them straight in till they stop and continue the rest of the process, tapping on them as time goes by.

You only have 3 things in there: Splined shift shaft, splined drive shaft, and a copper water tube. The only one of the three could be the shift shaft if it has enough slop to give you half of an inch of initial clearance. You ought to be able to look upwards toward the mid section and see if you can detect that the shaft has started to move away from the LU spline or it hasn't and what you got was just slop in the linkage.

If that's the problem, carefully applying pressure with 2 screwdriers on either side may help to dislodge it. If you prove that to be the problem, you may have to go topside and disconnect the shifter arm from the shaft so that the whole shaft can fall with the LU and then you work it loose when you get it out, or just leave it be and put it back just the way it came out. Other than being in your way while trying to do the pump, no reason to have to remove it.

Mark

 

[Mi duckdown]

Re: 1985 Mercury 60 hp lower unit removal

DRTYJERS. Have you done the measurements of putting a jet on a long shaft motor? You will have to raise the transom 5 to 6 inches.
Plus that 60 will run like a 40 hp. just hope you did your homework.

 

[oldman570]

Re: 1985 Mercury 60 hp lower unit removal

DRTYJERS. Have you done the measurements of putting a jet on a long shaft motor? You will have to raise the transom 5 to 6 inches.
Plus that 60 will run like a 40 hp. just hope you did your homework.

^1+ Jets are not the answer, unless they aree going to be used in shallow water and on a good tunnel hull. The rocks and dirt they eat will cost more in repairs than a good mud motor or gatortail.JMO
Oldman570

 

[drtyjers]

Re: 1985 Mercury 60 hp lower unit removal

Well I got the lower off!!!

BP Blaster never got to the drive shaft. I tried cutting one blade off propeller and running it but the water pump is fried so I only ran for 20 seconds 3 times. That did not work either so.....

I grabbed a 5 lb sledge/axe and beat the lower until the prop gears were exposed and prop broke off. There was a gear at the base of the drive shaft secured by a nut. I flipped to the axe side and beat directly down on the gear as hard as I could swing (without the risk of missing and chopping my leag off). After3 or 4 hard wacks I noticed the lower startring to seperate more. It slowly dropped another 1 1/2 before it actually came free.

So after a 2 day delay, I'm back at the rebuild.

I've done my homework on the Jet. I will be pushing a 17 ft aluminum bare bones bass boat (700 lbs dry) batteries moved to the front. Only carring a 6 gallon fuel tank (most trips will be a few miles up or downstream). I'm building a 6 inch transom riser to raise the motor up to proper level.

I'm hoping for high 20's with 2 guys and a gear in the shallows of the Delaware River.

Thanks for the responses!
Jake