trouble reinstalling a bottom end

[luskateer]

Have a 1980 Tower of Power 115 h.p. merc. I removed the lower unit and replaced the water pump housing and impeller. I'm trying to reinstall it and get about a half inch away from having it seated and it won't go. I'm wiggling the fly wheel and jiggling the shifter. I have it tilted up almost horizontal. my arms ache and i'm tired, the beers almost all gone....any helpful hints.
Rich

 

[Big Pete]

Re: trouble reinstalling a bottom end

I cant help sorry , but i am just asking apart from the fitting back problem you have now .. Was it an easy job ?

Reason i ask is i am just about to do my first lower end water pump on my Merc 80 ..

 

[Barnacle_Bill]

Re: trouble reinstalling a bottom end

Not sure how you are "wiggling" the flywheel but while you hold upward pressure on it have someone else turn the flywheel slowly. Usually they will pop into place doing that.

 

[luskateer]

Re: trouble reinstalling a bottom end

I cant help sorry , but i am just asking apart from the fitting back problem you have now .. Was it an easy job ?

Reason i ask is i am just about to do my first lower end water pump on my Merc 80 ..

I've removed several lower units on smaller motors. changing an impeller is pretty easy. Sometimes i take digital pics of stuff to be sure to get it back together right.

I'll give it another try tomorrow............and be sure to have less beer until the job is done....
rich

 

[Ken G]

Re: trouble reinstalling a bottom end

When dropping, and reinstalling, the lower units on the inline 4 and 6 cylinder Mercs of that era its best to have the motor in forward gear.

For reinstallation make sure both the upper end and the lower unit are in forward. As you raise the lower unit into position when the driveshaft meets the bottom of the crankshaft you can turn the propeller counterclockwise to get the splines to line up. You would have to have arms like a gorilla to be able to reach up and turn the flywheel with one hand while pushing up the lower unit with the other on an inline 6.

 

[emckelvy]

Re: trouble reinstalling a bottom end

If you leave the lower unit in forward, make sure the shift shaft remains properly positioned. When in fwd gear the shift shaft has about 270 degrees of free movement and there's only one correct position to reinstall. Spin the shift shaft CCW with pliers etc (cushion the jaws with tape to prevent damage to the shift shaft splines). When you feel a resistance it's about to shift into Neutral. But don't go so far as to shift to Neutral, leave it in this maximum CCW position while still in Fwd.

At this position, if you look at how the reverse lockout rod sticks out of the exhaust tower, you'll see that it will point to the middle of the ramp on the shift cam. If you haven't pulled the shift cam off the shaft (and no one has messed with it prior), it'll already be in the correct position.

Something else that'll cause a hangup is the rubber gasket for the exhaust tube. It should fit solidly against the inner walls of the gearcase, if it's bowed-in, it'll bind on the exhaust tube. Spread a thing coating of grease on the lower part of the exhaust tube, where it slides into the gasket.

Make sure that the plastic guide sleeve is in place in the upper water pump housing. This sleeve is what first catches the copper water tube as you're pushing the lower unit into place. Real hard to get things lined up without this tube. Many times it'll rattle upwards and stay on the copper supply tube when you pull the lower unit. It's just a slip fit into the pump and seats on top of the rubber water tube grommet (and the grommet does all the actual sealing of the water supply tube)

Another pesky, irritating thing to happen is when the shift shaft splines don't perfectly line up with the shift rod. Usually because there's a slight amount of pre-load on the shifter cable. So, maybe you end up a half-tooth off between the shift rod and the shift shaft. Makes it real hard to get things back together!

In that case, about the only solution is to disconnect the shift cable from the motor's shifter arm and manually move the shifter arm to proper alignment.

The above are the most common problem areas; hopefully that'll do the trick for you. Let us know if you're still having problems.

HTH & G'luck.........ed

 

[Moody Blue]

Re: trouble reinstalling a bottom end

I've had the same problem when replacing the LU on a 1971 Merc 800. In addition to the suggestions by emckelvy, I have found that with the motor tilted up that high that the shift shaft tends to "drop" slightly from where it would ideally line up with the splined coupling on the LU.

I fought with mine (on, off, on, off etc) for two hours. Checked everything and couldn't figure it out. Everything seemed to line up, but. Finally got a flashlight and peered into the small opening in the front of the leg just above the LU and there was the problem. I gave the shaft a little push up and it popped right into place and the LU slid into position. Hope this helps.

 

[luskateer]

Re: trouble reinstalling a bottom end

thanks for all the help on this. I was able to sych out the shifting position and also stick my finger in where the top of the shifting mates up. I think that and the promise of more beer facilitated the job with success . It's really a terrific feeling when it goes in. Reminds me of something else i used to do.
Onto the next problem......It won't start.....new thread......

 

[Ricky2]

Re: trouble reinstalling a bottom end

If you leave the lower unit in forward, make sure the shift shaft remains properly positioned. When in fwd gear the shift shaft has about 270 degrees of free movement and there's only one correct position to reinstall. Spin the shift shaft CCW with pliers etc (cushion the jaws with tape to prevent damage to the shift shaft splines). When you feel a resistance it's about to shift into Neutral. But don't go so far as to shift to Neutral, leave it in this maximum CCW position while still in Fwd.

At this position, if you look at how the reverse lockout rod sticks out of the exhaust tower, you'll see that it will point to the middle of the ramp on the shift cam. If you haven't pulled the shift cam off the shaft (and no one has messed with it prior), it'll already be in the correct position.

Something else that'll cause a hangup is the rubber gasket for the exhaust tube. It should fit solidly against the inner walls of the gearcase, if it's bowed-in, it'll bind on the exhaust tube. Spread a thing coating of grease on the lower part of the exhaust tube, where it slides into the gasket.

Make sure that the plastic guide sleeve is in place in the upper water pump housing. This sleeve is what first catches the copper water tube as you're pushing the lower unit into place. Real hard to get things lined up without this tube. Many times it'll rattle upwards and stay on the copper supply tube when you pull the lower unit. It's just a slip fit into the pump and seats on top of the rubber water tube grommet (and the grommet does all the actual sealing of the water supply tube)

Another pesky, irritating thing to happen is when the shift shaft splines don't perfectly line up with the shift rod. Usually because there's a slight amount of pre-load on the shifter cable. So, maybe you end up a half-tooth off between the shift rod and the shift shaft. Makes it real hard to get things back together!

In that case, about the only solution is to disconnect the shift cable from the motor's shifter arm and manually move the shifter arm to proper alignment.

The above are the most common problem areas; hopefully that'll do the trick for you. Let us know if you're still having problems.

HTH & G'luck.........ed

This is all very helpful. What if your replacing a lower unit that you have no idea what position the lower unit is in? The reason I ask is I just purchased a used unit and getting ready to install it.

 

[luskateer]

Re: trouble reinstalling a bottom end

For my 115 1980 inline 6 if you turn the shifter rod counter clock wise.(ccw) you'll feel a resistance just before it goes into neutral.....keep pressure on it turning ccw and it will slip into neutral.There's a detent internally for this position. you can check this by turning the prop by hand with no clicking or resistance. On mine i left it in neutral and the control in neutral. I was able to stick my forefinger in the front hole where the shifting rod connects and minipulate it. Felt alittle like a genocologist must feel.
Moved the flywheel a little and bango it's in......
Hope this helps
rich

 

[Ricky2]

Re: trouble reinstalling a bottom end

This is all very helpful. What if your replacing a lower unit that you have no idea what position the lower unit is in? The reason I ask is I just purchased a used unit and getting ready to install it.

 

[luskateer]

Re: trouble reinstalling a bottom end

I think if you rotate the prop clockwise and hear a clicking sound and when you turn it ccw it locks up .....its in forward...(Someone correct me if i'm a**backwards here)....... From that position you can do what i said in the previous message.
rich

 

[Ricky2]

Re: trouble reinstalling a bottom end

I will try it. Thank you.