67Mercury 950SS 95hp will not change gears

Forgive my ignorance on this please this is my first boat and it was given to me by a friend. I know a lot about a lot of things but motors and especially boat motors are not one of them. But I am good at fixing things around the house and yard and a lot of things.

It is a white and blue 1972 Mark Twain 16' with a 1967 Mercury 950SS Thunderbolt motor that is 95 hp. The motor looks great on the inside, he said it has been rebuilt within the last few years, and it did run great.

My friend took the boat out and I was on it a few times and it ran great, went quick and was powerful. He got a newer bigger boat so he gave me this one. It sat for a year and when I went to pick it up it would not start. It would crank over but would not spark. I asked my brother to help me, he thought it was the switch box cause he had a problem with his on his boat and he took it off, he put it back on after looking at it and looking for damage. We tried to start it again this spring and it still would not spark.

I towed it to my house and washed the boat cleaned it out, etc. I also went and bought a new battery, new fuel lines and new gas, and a new fuel filter. I have all of that installed and hooked up.

So here is the problem I am running into right now. I am trying to get the linkage completely hooked up for the shifting, but I have realized it has been in gear all of these times I have tried to start it, I have been around boats a little and knew the prop would spin just a little even when not in gear, like fluttering. So to see the prop spinning it did not occur to me that it was in GEAR. I have verified that it is in fact in gear, I know it is.

I have tried to push the shifter thing back that is in the motor (with the cover off) but it only will move back an inch and it will not click into neutral or reverse, it is stuck in forward. How can I get it to go into neutral when it is bound up? What can I do?

This is my first boat and I really want to get it running and in the water soon!

Thanks.

Josh

Re: 67Mercury 950SS 95hp will not change gears

Bump please

Re: 67Mercury 950SS 95hp will not change gears

bump. I would really like to try to get it running before memorial day. That is why I keep bumping it

Re: 67Mercury 950SS 95hp will not change gears

Josh, have you disconnected the shifter cable from the shift arm on the motor? It's possible there could be a problem in the control box or cable.

Otherwise, there's a possiblity that the reverse lock mechanism is binding.

Make sure the insides of the reverse lockout hooks are nestled on the stainless tilt pin.

If the outsides of the hooks are resting on the tilt pin, it'll bind up the shifting mechanism and could be the cause of your problem.

The motor is locked down in Neutral and Reverse. Only in Fwd gear are the hooks free to unlatch themselves from around the tilt pin when attempting to tilt the motor up out of the water.

So, you must shift the control box to Fwd before raising up the motor. The problem arises when the control box is shifted back to Neutral and left there, while lowering the motor back onto the tilt pin. Then the lockout hooks will not reingage the tilt pin, but rather will just rest on top of the pin.

So, check that out.

If that's not the case, with the motor tilted up and the shift arm in Fwd (all the way to the front of the motor), check the lockout hooks to make sure they are free to move.

If the hooks are bound up, this will also cause shifting problems. Some heat followed by penetrating oil may help. Clamp a set of Vise Grips around the lockout bar and work it back and forth while applying penetrant.

If none of the above seems to be the problem, you'll have to pull the lower unit to see what's going on with the shifting mechanism.

The shift shaft is at the front of the L/U, and is rotated CCW from Fwd gear, to shift to Neutral then Reverse. Don't turn the shaft any more CCW after you've reached Reverse (if it gets there).

If you get no results then, the gearbox is shot or someone has messed with the shift shaft (maybe pulled it out then just stuffed it back in - this doesn't work, BTW!).

Anyway, there's a few things to look at. Be sure to remove the trim tab (bolt thru the top) to reveal the hidden L/U mounting bolt underneath. Other than that, removal of the L/U is pretty straightforward.

G'luck and keep us posted........ed

Re: 67Mercury 950SS 95hp will not change gears

emckelvy Thank you for the quick reply!

Yes, I did have the cable unhooked when I was trying to get it to switch gears. As a matter of fact I had the cover off of the motor and I has pushing on it by hand very hard to get it to shift. It would not click back into neutral. I will print off the suggestion you gave me and see if that will help tonight.

Thank you for replying to me. I can't wait to get my Tower of Power out on the water!

Josh

Re: 67Mercury 950SS 95hp will not change gears

My progress so far:
The reverse lock is functioning properly. Thanks for pointing that out, I never even thought of that, but either way it is working.


ok I got the lower unit off. I had never done that before but with some searching I found a great picture walkthrough here for removing the lower unit:
http://forums.iboats.com/showthread.php?t=287508

So lower unit is off a couple questions...

I am confused. Even with the lower unit off I cannot make the shift mechanism travel any more than one inch. One inch from the front and that is it. It seems by taking the lower unit off that should move now right?

And please explain what I am looking at here in my garage. I love to learn stuff. On the lower unit now that it is off from the front back, I can see a copper tube (oil tube?), a longer tube with splines (drive shaft?), and near the back I see a little 1.5 inch bar sticking out with five grooves in it. I can see the corresponding place where that goes into the motor, is that the transmission part that shifts the motor from Forward, Neutral and Reverse?
Also if that is the tranny connector, why can I still not move the shift lever at the top of the motor, where it connects to the cable?

UPDATE> I got it to move! I have managed to get the shift lever to move up top AND I have moved the part coming out of the lower unit in the lower unit with a pair of pliers, it seems to be moving OK now but what should I do to make sure it continues to function properly before putting the lower unit back on.

Also while I was wiggling around the shift cable mechanism up top a white plastic peice fell out of the motor that goes on the bottom of the motor. O know where it came from, where the shifting mechanism is on the bottom of the motor, but does the pointed part go up or down?

Re: 67Mercury 950SS 95hp will not change gears

The shifter arm up in the powerhead should have free range of motion from the front of the guide that it rides in, all the way to the back. One inch of travel ain't gonna make it and maybe that's why you're not getting shifting action.

The arm is a pretty simple affair and just slides fore and aft. There's a 1/4" stud sticking up from the arm. A washer then a small spring fits over then stud, then a plastic guide block; this block fits into the insides of the bottom side of the shifter arm guide.

Topside of the shifter arm guide, goes a thin plastic, sorta-rectangular-shaped "wear plate" that is greased up and rubs on the shift guide. Then the "control cable fastening latch" goes on the stud, followed by a flat washer and fine-threaded locknut. The cable latch, when tightened down, retains the end of the shift cable.

If the locknut is tightened down too much, it'll cause the whole mess to bind on the shift arm. So maybe try loosening the nut a bit and see what happens. Just greasing the shifter arm guide might help.

It's also possible to have a broken shifter arm guide. The busted part might jam on the shift lever and keep it from traveling all the way to the back.

With the lower unit off, there's really nothing to keep the upper shift arm/rod from moving except for its contact with the shift guide.

Far as the lower unit goes, at the front of the lower unit (opposite the prop end) is the smaller splined shift shaft. The large shaft of course is the driveshaft. The copper tube is the water supply and is supposed to remain in the exhaust tower, not be stuck in the water pump cover (which it kinda sounds like, the way you described).

Never fear, the copper tube just pulls out of the pump, there's a rubber grommet it slips into. You'd need to look up the center of the exhaust tower to find the hole where the water tube fits. A dab of grease or Permatex gasket dressing on the end of the tube and Up it goes!

Since you've got the lower unit down, might as well replace the impeller. Your local Merc dlr will have one in stock, or if you have a NAPA nearby they can get them too. (maybe not this weekend, though!). Probably will wanna pick up at least a water pump body gasket or just order a repair kit which will have impeller, impeller key, pump gaskets & pump wear plate.

Don't forget to pick up a new O-ring for the groove in the driveshaft, up there by the splines. The O-ring seals the driveshaft where it enters the crankshaft, keeping water out of the splines. If the O-ring is bad or missing, water in the splines will rust/rot out the crank and driveshaft. If you can't find the factory item just get a suitable O-ring from NAPA, they'll usually have a big box with various sizes to choose from. Be sure to use waterproof marine boat bearing grease on the driveshaft spines and all bolts/studs. Sta-Lube marine grease is commonly found, Wal-Mart also carries a line of inexpensive marine grease that'll work as well.

On the shifter, with the L/U in forward there's about 270 degrees of free play in the shift shaft. As you rotate it CCW you'll get to a spot where there's some resistance; more rotation shifts to Neutral. One more 'click' CCW from Neutral gets you into Reverse. If there's some resistance going into Reverse, just spin the propshaft as you shift and it should go right in. Don't go any further CCW once in Reverse.

Once you check out the gear shift and it's Yay or Nay, you'll have a better idea whether the top or bottom of the motor is giving you problems.

Take a look at the parts diagrams for your motor here, it'll show you exactly what parts there are and how they stack up:

http://www.mercruiserparts.com/SelectModelType3.asp?class_id=2

HTH & let us know what you find.............ed

Re: 67Mercury 950SS 95hp will not change gears

Thank you so much for your help! You are a Godsend.

How do I know when the white plastic piece in the lower unit is indicating neutral? The white piece in the lower unit has a part at the top of it that is about a half inch wide. What way should that be pointing toward to so I know it is in neutral? towards the front, back, side?

And what happens if I click it past where I am supposed to? Out if curiosity?

Re: 67Mercury 950SS 95hp will not change gears

jhouser said:

UPDATE> I got it to move! I have managed to get the shift lever to move up top AND I have moved the part coming out of the lower unit in the lower unit with a pair of pliers, it seems to be moving OK now but what should I do to make sure it continues to function properly before putting the lower unit back on.

Also while I was wiggling around the shift cable mechanism up top a white plastic peice fell out of the motor that goes on the bottom of the motor. O know where it came from, where the shifting mechanism is on the bottom of the motor, but does the pointed part go up or down?

Click to expand...

That's the guide for the reverse lockout rod. The rod passes right thru it. This guide piece also nestles up into the end of the upper shift rod. There should be only one way you can install it where it'll go fully up into the center section. As I recall, one end of the guide is closed off such that only the shift shaft in the lower unit will fit thru the hole, on its way to the upper shift rod.

The other end of the guide is large enough to accept the end of the upper shift rod.

BTW congrats on getting the shifter arm to move, but just a caveat it should move fairly freely. Try loosening the locknut on the latch as per the previous post. There should be a bit of free play on the shift arm, you should be able to lift it up a bit and feel the spring action.

If the spring is "two-blocked" by having the locknut too tight, the shifter arm is gonna bind like crazy. Grease the heck out of all the friction surfaces, too. It may be messy but it needs the lube!

Have Fun...........ed

p.s. when you install the lower unit, if you position the shift shaft to Neutral, and place the shifter arm at about the middle of its travel on the shift arm guide, the shifter should go back together just right. There's only one position where it'll shift correctly, using the full range of motion in the 'track'.

If the shift rod doesn't line up quite right with the L/U shift shaft, just move the arm a bit until it aligns. Once you have the L/U bolted up enough to close the gap, test-shift to see if you've got it correct. The gearbox won't shift into reverse until the arm is close to the very end of its travel to the rear of the motor.

Ok, so I may have messed up a little

Ok, so I may have messed up a little

Ok, so I may have messed up a little
But I think it can be fixed. Let me explain...

Earlier today when I was at my office I was browsing iboats on lunch. I was looking for ways to get my boat to shift into neutral. I found a post by someone (it may have been you because I found your posts very informative, so I searched by all posts by you so that may have been how I found this...)

Anyways, I had found something that said if having a problem shifting then to turn the propeller and just before it clicks to leave it right there and then try to shift. I tried that earlier and it still would not work, so I went with the steps you had recommended, which was remove the lower unit, etc. I removed the lower unit as you know and once it was off I started messing with the shift mechanism in the lower unit. It has about 270 degrees of free play and when I say free play I mean FREE play, no resistance at all. As I said before I have some mechanical knowledge and I knew that nothing 'mechanical' was happening with 100% free movement. So I went the other way and turned the splined shift mechanism with a pair of vice grips. I got it to move as I said. It clicked hard a few times and I thought that must have been forward neutral and reverse. I am sitting down now and I am not sure if it was ccw or cw.

What I have realized is that the prop/drive shaft was still in this position when I had it separated from the rest of the motor, when I was getting the 'no resistence' turning, I mean there there is no resistance. None. but when I click it into gear (the prop shaft) I get resistance everywhere, no free play at all. What am I missing? What should I do to make sure that it is in Top Dead Center (I know that is the wrong terminology ), what I really mean is the correct position to make sure it is in neutral. How do I know the position of the white piece to make sure it is in neutral?

Re: Ok, so I may have messed up a little

Re: Ok, so I may have messed up a little

jhouser said:

How do I know the position of the white piece to make sure it is in neutral?

Click to expand...

I don't think you're messed up at all. I'm thinkin' it's just a bit of cornfusion about how the ol' Mercs go about shifting.

The 'white piece' on the shift shaft is the shift cam and all it does is to block the downfall of the reverse lockout rod when the L/U is shifted to neutral or reverse. As long as you haven't pulled the shift cam off the shift shaft and put it back on in a different position, you're OK.

Far as the propshaft turning, you're probably in reverse. The propshaft will come up against resistance in both directions with little free play, only when in reverse. In forward gear, rotating the propshaft clockwise will get you a bunch of clicking, the other way will want to drive the driveshaft backwards.

Here's something for you to do. Looking downwards at the driveshaft, turn it clockwise. Note which way the propshaft is turning.

If the propshaft is turning CCW when you're looking at the Arse-End of the prop, you're in reverse. If the propshaft turns CW you're in forward.

And your comment about the shift shaft having little to no resistance in fwd is exactly correct. The reason for this is that when you shift to neutral and reverse, the shift shaft is actually pushing on something, and that something is the shift plunger, pushing the shift clutch against very heavy spring pressure, to the neutral and reverse positions.

Now, when you 'shift' to forward, what you're actually doing is relieving all pressure on the shift plunger/spring/clutch dog, and the shift clutch is forced by spring pressure hard against the 'cogs' of the forward gear. This is so that the clutch does not slip and cause damage to the 'cogs' and 'dogs'.

The shift cam is doing little to no work in fwd gear and this is why there's no resistance. Also why you can turn the shift shaft a whole bunch. There is no stop to prevent the shaft from moving in this direction (clockwise).

However, when you turn the shift shaft CCW you present the ramp on the cam to the shift plunger. The ramp on the metal shift cam, in the bowels of the lower unit, presses on the shift plunger to cause shifting action. And there is a detent or 'notch' in the cam exactly where neutral is supposed to be.

When you turn the shift shaft some more, you reach the 'high point' of the cam. This presses on the shift plunger even more, driving the shift clutch into the reverse gear which causes the propshaft to rotate in the opposite direction. If you were to rotate the shift shaft even more CCW past the reverse position, you'd actually 'fall off' the cam and be back in forward! Then rotate another 270 degrees and guess what, you're back to the spot where it'll shift to Neutral!

But you don't want to shift CCW past reverse. Hard on the parts. So basically the point you want to find is Neutral. Where the propshaft spins easily in both directions.

From Neutral, it's just one click CCW to reverse. And from Neutral, it's just one click CW to forward.

What messes everybody up on the Mercs is the amount of free play in the shift shaft, when in fwd gear. That's why you'll see the recommendation again and again to shift the lower unit to Neutral before reinstalling. Since there is a detent, it'll tend to stay in Neutral until you get it all back together.

With forward, you can see how the shift shaft can be all over the map and still be in fwd. But if it's not in the right spot when you reassemble, guess what, it's gonna stay in fwd!

Unless you set it up properly. Which means, when you're in fwd gear the only correct position for the shift shaft is to be all the way CCW in its 270 degree range of motion, until any more movement CCW shifts to neutral.

So you can see there's really very little movement the shift shaft goes thru to shift. You just have to find Neutral and that makes it real easy to set up.

Anyway, hopefully this long-winded post makes sense. When you're done you'll certainly be able to get your Merc Qual-Card signed off!

Cheers........ed

Re: 67Mercury 950SS 95hp will not change gears

Still confused on how to make sure it is in nuetral before I reattache the lower unit.

Hoping I can figure this out or get some advice.

I still have the lower unit off because I have messed around with it for a couple of hours and I can't get it into neutral and know it is neutral for sure

Ed, you said "So basically the point you want to find is Neutral. Where the propshaft spins easily in both directions."

Problem is no matter how many clicks I go when turning the shift shaft I cannot find a place where I can spin the Prop Shaft in either direction without the Drive shaft turning. I can click the shift shaft and find where to make the prop shaft turn in either CW or CCW direction but I can't find where to make it so the prop shaft spin in both directions without moving the drive shaft.

What am I missing?

Thanks.

Re: 67Mercury 950SS 95hp will not change gears

OK I got it swiched into neutral and have the lower unit attached again.

I still am getting no spark and I have troubleshooted the switchbox, and according to the steps I have the switchbox is the problem.

I am getting ready to order it. I just want to make sure it is the right one that I order. My motor is a 1967 based on Serial Number. There are two switchbox options. Which one do I order?


Switchbox number 1
Switch Box replaces part # 332-2803A 3, 332-2803 4,
Hp Year Model Cylinder
95 1966-1967 950 6
110 1966-1967 1100 6


Switchbox number 2
Switch Box replaces part # 332-2986A 21, 332-2986A 25, 332-2986A 27,
Fits most 1967-1977 4 and 6 cylinder engines

Re: 67Mercury 950SS 95hp will not change gears

Does your distributor have 2 or 3 wires coming out?

The old-style "1100SS" ign was points fired to a CDI switchbox. This switchbox was unique to the type of ign. Both wires coming out of the distributor went to one terminal on the switchbox.

Later versions used the 'garden variety' electronic trigger with 3 wires, going to separate terminals on the switchbox.

If yours is the latter, "Switchbox Number 2" is likely the correct replacement. Plenty of them available aftermarket and even used on eBay. If you are using an old-style Quicksilver tach and the tach wire goes to the switchbox instead of the rectifier, you'll want to make sure to get a 6-cylinder box (if getting a used one). Otherwise the tach won't work. If you get a new aftermarket replacement box, I don't think they have a tach terminal and you'd have to upgrade your tach. Note if you have a tach and it's running off one of the yellow terminals on the rectifier, you can use either 4 or 6-cyl switchbox.

If you think yours is the earlier-style, I'd definitely look for part numbers on your switchbox and make sure the "Switchbox Number 1" is the correct replacement. You should be able to tell by a pic because they were completely different in terminal configuration between the different styles.

HTH.........ed

Re: 67Mercury 950SS 95hp will not change gears

Ed,

Your help has been great in all of this. I am learning a LOT.

I am ordering the switch box for it. It was the one with three wires btw.

While waiting on that to arrive I wanted to see if you could help me understand something when you get a chance, which is the shift box that is next to the driver's seat.

I have recently realized after messing with it with a friend there I do not really understand it and how the levers work.

There are two levers, a big one that is closer to the driver and another smaller black one that is closer to the outside of the boat. After riding on my Uncle's new boat I assumed that like his one was for throttle and one was for shifting but after getting them hooked up it seams that this is not the case, because when one is moved then the other moves as well at some points.

Which one does what and how are they used? I thought the big one was for fuel only and would only move the throttle line, and the small black one was for forward neutral and revers selection but since on the motor both move when the larger handle is moved I am confused...

Thanks,

Josh

Re: 67Mercury 950SS 95hp will not change gears

How does the shifting work on this motor??

There are two levers, a big one that is closer to the driver and another smaller black one that is closer to the outside of the boat. After riding on my Uncle's new boat I assumed that like his one was for throttle and one was for shifting but after getting them hooked up it seams that this is not the case, because when one is moved then the other moves as well at some points.

Which one does what and how are they used? I thought the big one was for fuel only and would only move the throttle line, and the small black one was for forward neutral and revers selection but since on the motor both move when the larger handle is moved I am confused...

Thanks,

Josh

Re: 67Mercury 950SS 95hp will not change gears

Assuming you have a MerControl controller, they operate as follows.

The large lever is both throttle AND gear shift. The small lever is the fast idle throttle control to be used ONLY when in neutral.

Back to the large lever. When vertical, it is in neutral and throttle is at idle. As you move the lever forward, the controller first shifts gears in the lower unit to forward and then gradually increases throttle as you move the lever further forward. Same operation when you pull the lever back, but you now go into reverse gear from neutral.

The small lever is used for starting the motor ONLY. It allows for throttle operation while in neutral to help in starting the motor. Lift the lever approx 1/2 way up (trial and error), push and HOLD the choke button and then turn the key to start. Release the choke button as the motor fires up and adjust the small lever to vary the RPM.

The small lever must be fully down before you shift into gear or you will damage the internal mechanism.

I know this is an old post... but hoping somebody will answer my call. I have the exact same motor, and am also new to boat motors.... well any motor to exact. I've overcome rebuilding the distributer. I had no tell tale, so rebuilt the water pump basically. It runs, and stays running. Noticed that it seemed to be stuck in forward at low RPM's. When I would push forward on the throttle, nothing would happen until I pushed it all the way forward, and it took off like crazy. No in between. (Keep in mind I'm in my driveway using muffs) So I replaced the control cables. Helped with the throttle problem, but still stuck in forward. So took the cables back off and started it back up. The shifter slide thingy moves freely when detached from the cable, but does not change gears. No clicks, no nothing it just slides back and forth. The shift link assembly is moving, but can't see if it's detached from anything, expect there is a bronze looking bracket down there with a hole in the middle. Not sure what it is, but it doesn't seem to be attached to anything. Thoughts?
Is this a linkage problem, or do you think it's something in the lower unit, or even the reverse lock out thing with the tilt pin??? Again, sorry, this is all new to me. As discouraged as I was today, thinking I was about done with the rebuild, I am kinda excited to learn more about how these old things work.
Thank you in advance.

cfaurote said:

I know this is an old post... but hoping somebody will answer my call. I have the exact same motor, and am also new to boat motors.... well any motor to exact. I've overcome rebuilding the distributer. I had no tell tale, so rebuilt the water pump basically. It runs, and stays running. Noticed that it seemed to be stuck in forward at low RPM's. When I would push forward on the throttle, nothing would happen until I pushed it all the way forward, and it took off like crazy. No in between. (Keep in mind I'm in my driveway using muffs) So I replaced the control cables. Helped with the throttle problem, but still stuck in forward. So took the cables back off and started it back up. The shifter slide thingy moves freely when detached from the cable, but does not change gears. No clicks, no nothing it just slides back and forth. The shift link assembly is moving, but can't see if it's detached from anything, expect there is a bronze looking bracket down there with a hole in the middle. Not sure what it is, but it doesn't seem to be attached to anything. Thoughts?
Is this a linkage problem, or do you think it's something in the lower unit, or even the reverse lock out thing with the tilt pin??? Again, sorry, this is all new to me. As discouraged as I was today, thinking I was about done with the rebuild, I am kinda excited to learn more about how these old things work.
Thank you in advance.

Click to expand...

Yes, this is an old post. We prefer you start new threads rather than piggy-backing on an old thread which is ignored by most members. If you want help, read the Help Tip on top of the page and start a new thread. You have a much better chance at getting an answer.

You are going to be dropping the lower unit, then making sure the shift and control are in the same gear. Right now the two are out of sync.

Closed.