94 Mariner 75hp gear shift question

[rvrlaxn]

Pulled off the lower unit to change water pump. No problem. cannot get the lower unit to go into N on the bench. Did not have any problems before removal. Can rotate the LU shifter about 180 and go into R, but I have to hold it there. Put it back on the motor after a hell of a fight to get it to go the final 1/4 inch. Did not force it, but it took many tries. Bumped it over, but it is always in Fwd. Pulled it back off. Read that it should be in FWD prior to install. Looking down at the LU is FWD full CCW with a click? And then put the boat in FWD? That should work right? She does not want to go. Any tricks?
Thanks in advance.

 

[CharlieB]

Re: 94 Mariner 75hp gear shift question

I never remember if it is CW or CCW

Think of the shift cam as a ramp on one side and a very steep slope on the other, turning one direction (against the steep slope it is next to impossible to rotate, while turning the other direction it will run up the ramp, keep turning and it will fall off the steep slope again.

The bottom of that steep slope is FWD, the top is REV.

Midway up the slope is a smalll detent for Neu, and another detent on top for REV.

Either Neu or REV will work well for reassembly as long as the shifter control is set to the same position. Advantage to REV is you can more easily rotate the prop to align the splines in the vert shaft and crank, if using Neu it may be dificullt to reach up to rotate the flywheel.

FWD is mandatory for I/O's, O/b's like either Neu or REV

 

[rvrlaxn]

Re: 94 Mariner 75hp gear shift question

I must be missing something. To put the LU in R i have to turn it full CW looking down at the removed LU and hold it there. If it comes even a little bit CCW if goes back to Fwd. I cannot seem to put the LU in Neu on the bench. I had no problems prior to removal.

 

[carholme]

Re: 94 Mariner 75hp gear shift question

rvlaxn;

Here is a picture of the shift cam which acts against the pointed end of the cam follower

http://img687.imageshack.us/i/glm11185.jpg/

and here is a picture of the gear positions.

http://img267.imageshack.us/i/shiftrange.jpg/

You should be able to turn the shift shaft through a range of about 180 degrees before you come up against the shift cam.

So, rotate the shift rod CCW until you feel it stop. Then, using a socket to fit the shift shaft splines or pliers, (with a rag around the splines) you will feel some force but rotate the shft CCW until you feel it click into position.

The gear positions are verified by the prop:

Forward: prop or prop shaft should not turn CCW
Neutral: """"""""""""""""""""""""""""" turn freely in either direction
Reverse: """"""""""""""""""""""""""""" not turn CW

Neutral is very sensitive and that is why most people elect to have the boat controls set to Fwd and the LU set to the same prior to installation of the LU. Whatever you choose the boat must be in the same gear as the LU.

Here is a parts page showing item, 46, the cam follower:

http://www.crowleymarine.com/mercury-outboard/parts/554_320.cfm

Here is the same showing the position of the shift cam:

http://www.crowleymarine.com/mercury-outboard/parts/554_310.cfm

Hope this helps.

Gerry

 

[rvrlaxn]

Re: 94 Mariner 75hp gear shift question

Gerry,
Awesome, just the info I was looking for. I will go for reinstall in the am. Will let the forum know how it turns out, and any lessons learned.

 

[rvrlaxn]

Re: 94 Mariner 75hp gear shift question

Still having problems. At either end of the 180 if I use some pliers and turn it past the resistance it goes into R. It will not stay there without holding it there. It will spring back from either end to be in F. I cannot seem to find N on the bench. I put the boat in F and watched which way it turned the shift rod. I put the LU all the way CW up to the resistance and installed. It is stuck in F. F being "clack clack clack" when the prop is spun CW by hand, and turns the motor backwards when turned CCW. Prop is in this condition regardless of the boat configuration. What am I doing wrong?

 

[carholme]

Re: 94 Mariner 75hp gear shift question

rvlaxn;

Before the LU is installed, you must be certain that the three gear positions are available and verified in each position by turning the prop. If you cannot be certain of this, it is pointless installing the LU.

You say that you cannot find Neutral on the bench. At this point, to me there is something wrong. Yes, they are sensitive but there should be a definite engagement in each gear position and certainly enough that you can leave it there and check rotation of the prop.

After the LU was dropped the first time, was the water pump the only maintenence you performed? Nothing else was touched?

If it was only the water pump that was done, it almost says that the shift cam is worn (unlikely on a 1994) or there is something wrong with the follower/spring.

Gerry

 

[rvrlaxn]

Re: 94 Mariner 75hp gear shift question

Got it. I was just to hesitant to put to much torque on the input shaft on the bench. I went CW to the stop and then turned really hard. Now I was in F on the in the right place. A little CCW and nicely in N and a little more CCW and R. Put it back on and all is good. Just to afraid to turn it so hard on the bench, did not want to screw anything up. Thanks to all for your help.

 

[carholme]

Re: 94 Mariner 75hp gear shift question

rvrlaxn;

Glad for you that it worked out and just another learning experience to notch in your cap. Hope all goes well on the water.

Gerry