i need help re-installing lower unit

[john530]

i have a early 70's mercury 65hp outboard. I have the motor on my boat, i had started it and ran it for awhile. While running i checked FNR all gears worked fine, then realized water pump wasn't working. I dropped lower unit replaced impellor went to put lower unit back in, i hadn't messed with gear now it's like i cant get into forward gear. I put the lower unit in neutral and put the controls in neutral put the lower unit back up and still, control box is really stiff, if i shove it into forward gear and spin the prop clockwise it just rachets. Its like i can't find forward on the lower unit but i can get neutral and reverse. I don't really know where to go from here.

 

[Gomer50]

Re: i need help re-installing lower unit

When in forward the prop will rachet one way and be locked the other way,when in reverse the prop wil be locked both ways.

 

[john530]

Re: i need help re-installing lower unit

So the ratcheting is ok then. I was reading where people were saying it will spin clockwise in forward and then ratchet in reverse. So i guess i had it they just got me confused. So forward will ratchet clockwise, neutral will spin freely, and reverse will lock both ways, is that correct? And is it better to install lower unit in forward or neutral or does it not matter?

 

[Gomer50]

Re: i need help re-installing lower unit

you are correct rachet in forward locked in reverse.As for reinstalling the lower unit you will get different opinions on being in forward/neutral and sometimes reverse.I personally choose to be in neutral when doing this.

 

[Fed]

Re: i need help re-installing lower unit

I've had a couple of those John & they ratcheted in forward & reverse.
If you looked very carefully at the shift rod splines you would have seen that they can only go on 1 way, hard to explain but the splines are offset.
If they're not aligned properly you can push the shift rod up until it hits somewhere under the powerhead, probably under the bottom carby & if you force it with the bolts you can shatter the shift rod which means pulling the powerhead of to replace it. (Yes I did it
Doing it in gear gives you the option of turning the prop to help align the driveshaft splines if you don't have a helper to turn the flywheel.

I don't really know where to go from here.

Drop it back down then put it back up very calmly & carefully, 2 people helps a lot & some long skinny pliers to wiggle the shift rod, good luck.

 

[john530]

Re: i need help re-installing lower unit

now im really confused. So i took that advice and put the lower unit into forward gear and put the boat in forward gear, installed the lower unit then i put the boat in neutral but the motor is still in forward. So i dropped the unit again, put the unit into neutral put the boat in neutral, re-installed the unit then shifted the boat into forward but the motor is still in neutral. I have no idea, i don't know if i have my ramp on the shift splines in the right position i just don't know anymore and i'm kind of getting tired of pulling this thing. Anymore information would help. Thank you.

 

[nicknight]

Re: i need help re-installing lower unit

Different models will have different procedures.
My 2007 Merc says to put into forward, take off the lower unit, leave in forward and re-install. the year before it was a different procedure and some linkage had to get disconnected.
I remember the one time I did not do it the way the manual said and my gearing was off.

If someone here does not give you the procedure for you exact model I would check out the library for a service manual....or try doing the same in reverse?

 

[Fed]

Re: i need help re-installing lower unit

Once this is over John you will wonder what all the fuss was about.

Firstly check the shift spline coming out of the gearbox & see if the splines are offset so that it will only go on one way, that is for me because it's been so long I can't remember & I'd like to know.

Then make sure that spline hasn't been damaged by using pliers on it, if so clean it up with a file so you're sure it will go in smoothly. If you use a tool to turn that shaft then use some cardboard to protect it from burrs.

Put some grease on the drive shaft splines & the gearbox shift splines. Not up the shift shaft hole.

Put the gearbox in forward, put the controller in forward then slide it up.

The problems you can encounter on your own is the drive shaft splines not lining up and you fix this by turning the prop counter clockwise which will turn the drive shaft until they slip in.
If you have a helper this can be done by moving the flywheel.

Second problem is the shift shaft spline not lining up and you fix this by very slightly moving the shift shaft with long nose pliers until it slides in.
If you have a helper this can be done by moving the shift lever a little up at the motor.

Make sure you have a nut handy to hold it up with because you won't feel like starting over once you get it in and find out you can't reach one. Good luck.

 

[john530]

Re: i need help re-installing lower unit

You know one gear i knew i had for sure was reverse, and i had called a boat mechanic in my area and they told me that when the gear box is in reverse the flat part of the shoe should be facing forward. So i put the gear box in reverse put the shoe with the flat facing forward and put the control in reverse put the lower unit up it slid right up i just put a couple of nuts on to hold it, then i shift the boat into neutral but the motor is still just stuck in reverse. Its the same thing if i install it in neutral or forward, as soon as i shift it into a different gear its just stuck in whatever gear the lower unit is in. Now its all messed up, i don't know if i have the shoe in the right spot. And when i put the gear box in forward gear and turn the driveshaft clockwise the prop spins clockwise, but if i try to spin the prop clockwise it just rachets and the shift shaft slips like its not engaging or something. I can't figure it out for the life of me and im pretty good with stuff like this, but i have no manual or specs on my motor so im going off what people are telling me. It just seems no matter how i do it it doesn't change anything. If anyone could help me or maybe knows where that shoe goes and which way to turn the shift shaft for the different gears. The splines aren't offset, i checked that out to.

 

[Fed]

Re: i need help re-installing lower unit

When you shift into forward gear the prop is supposed to ratchet clockwise and lock up tight counter clockwise.


When in neutral the prop should spin freely.

When you shift to reverse the prop should be able to ratchet counter clockwise and lock up tight clockwise.

Think about it from the prop shaft point of view.

 

[john530]

Re: i need help re-installing lower unit

Ive put the unit into forward and the boat in forward then installed the unit. After ive installed it if i shift into neutral the prop doesn't free spin. The motor just stays in whatever gear i installed it in. I dont think i have the ramp on the shift shaft in the right position. Its like it just wont change gears once its installed. And ive had the lower unit off and had someone move my gear shift while i watch the rod in the mid section, and it doesnt move i dont know if thats normal or not.

 

[Fed]

Re: i need help re-installing lower unit

No that's not normal, when you move your shift controller it should move the control cable that connects to the arm on the top of the shift rod.
Have a look where the shift cable enters the motor, get someone to move the controller and see if the shift cable is moving at the motor.
If you had a broken shift shaft like me then the bottom half of it would fall out on the ground.

 

[justbe88]

Re: i need help re-installing lower unit

hi, folks. this is my very first post here. i just got my first boat a 1978 monark with a 1978 115hp mercury outboard. it had been sitting for a while so i decided to replace my water pump impeller. things were going really well, after i found that hidden bolt to get the lower unit off...lol. i now have a boat that wont go into any gear...yep, stuck in neutral. needless to say i am following this thread with much interest...lol. i just wanted to say thank you to everyone for so willingly sharing your knowledge and experience. good luck, john530...you're not alone

 

[john530]

Re: i need help re-installing lower unit

Well when i shift the control i can see the shifter inside the motor moving in all three gears but the rod in the mid section doesn't move up or down, but everything else moves just not that rod that engages the ramp on the shift shaft in the lower unit. so i don't know if something came apart in the mid section or not. I can push that little rod up and then it springs back, but if i put it in gear using the controls it doesnt move up or down. I guess i'm going to have to bring it in. We all know what B.O.A.T. stands for ( bust out another thousand)

 

[Fed]

Re: i need help re-installing lower unit

John I had 65HP 3 cylinder (650) Bluebands, are we talking the same motor here.
My shift shafts used to rotate to change gear not go up & down.
They were just a steel shaft with a female splined coupling on the bottom and an alloy lever at the top, When the lever at the top was moved backwards & forwards the shift shaft rotated maybe about 90 degrees.

 

[john530]

Re: i need help re-installing lower unit

Yes this is the same motor you had. 65 Hp bluebands. I thought that rod engaged the shoe(ramp) that slips over the shift shaft in the lower unit and that when that rod engaged it would move the ramp therefor shifting gears. So the shift shaft is splined into the mid section. what does that shoe(ramp) thing do, and whats that rod that you can see up inside the mid section. I'm not really sure how these things work, i have been figuring it out by myself and have been doing pretty well until i hit this point. I was just figuring that if the lower unit is in neutral and the boat is in neutral, and everything slides up nice and easy which it does that everything should line up and i should be able to shift into my other gears, but that is not the case. It seems like it shouldn't be this hard to get to go, i'm assuming i have something just alittle off but i cannot figure out what it is.

 

[Fed]

Re: i need help re-installing lower unit

When the lower unit is out & on the floor do you see a male splined shaft sticking out of the gearbox, it would be approximately 2'' tall.
If not do you see a hole that looks down into the gearbox?
Can you take a couple of pics, that would answer all the questions.

 

[john530]

Re: i need help re-installing lower unit

I will take some pictures and get them up later today.

 

[john530]

Re: i need help re-installing lower unit

Well everybody i figured out the problem. The shift shaft with the female splines is bent and not lining up with the male splined end. Luckily i do not have to remove the power head to get that shaft out of there. Thank you everyone for all of the help and input, i appreciate it much.