Need help dropping lower unit

[poppys pride]

I,m trying to remove the lower unit on my 1968 merc 500 thunderbolt. I cannot get the lower unit to come down. I'm assuming it is caught in the crank splines. Any suggestions? I'm taking it off because the motor will not shift into forward after a clunking noise.How can I get the splines to loosen to inspect gearcase?

 

[Moody Blue]

Re: Need help dropping lower unit

Not familiar with that exact motor but can offer a little info from motors I've worked on.

Are you certain ALL the fasteners are removed? There is usually one hidden under the trim tab. Have to remove the trim tab to get at it. There are usually at least 5 nuts/bolts holding the LU on.

If the unit drops even a little, you can place wooden shims into the space evenly around the perimeter and gradually drive the shims in further and further. Do it gradually and evenly all around.

 

[dbmstr124]

Re: Need help dropping lower unit

well said to the man above...I just got done putting mine back on 20 mins ago due to a water pump...Pull off the plastic cap on the back of the lower unit and there is a 1/2" bolt there...it will come out dropping the trim tab underneath it, then inside there is another 5/8" or 9/16" bolt...that will bring it down.

 

[keiron49]

Re: Need help dropping lower unit

i had to change my impellor and took the long way round to find the hidden bolt, once all bolts removed it dropped about an inch and then stuck tight. as mentioned previously by moody blue , i just gently prised it down with some timber and it end up just being a load og gunk stck in the exhaust bit and once cleaned out it went back in lovely.

 

[tredragon]

Re: Need help dropping lower unit

Not familiar with that exact motor but can offer a little info from motors I've worked on.

Are you certain ALL the fasteners are removed? There is usually one hidden under the trim tab. Have to remove the trim tab to get at it. There are usually at least 5 nuts/bolts holding the LU on.

If the unit drops even a little, you can place wooden shims into the space evenly around the perimeter and gradually drive the shims in further and further. Do it gradually and evenly all around.

On my 68 500 I have a hole above the trim tab, dropped a 3/8 hex wrench into there, back bolt out... trim tab drops, a 9/16 nut is on the bottom side where the trim tab fell out of. Then I back the front two 5/8 nuts (there is one on either side) evenly and they push the LU away from the rest.

 

[roger-s]

Re: Need help dropping lower unit

dont know to much about older ones but dont forget the shifter rod bolt i know on my 120 evinrude the bolt was under the carbs at the bottom of the powerhead

 

[tredragon]

Re: Need help dropping lower unit

I dont' have anything up that high. All on the lower unit... like bottom 12" of the motor.