1975 Merc 110 9.8hp shifter binding

[fhafer]

My 9.8 shifter is binding. I dropped the lower unit....bind is in the upper end. Appears there is too much slop causing the two gears to bind. Anyone ever experience this? What was the fix?

When I move the shift lever all the way back to reverse I can spin the vertical shift shaft and gear with a flat-head screw driver without moving the gear in the horizontal shifter shaft. May be a missing tooth on one of the gears?

Thanks.

 

[8075mercury]

Re: 1975 Merc 110 9.8hp shifter binding

Good news the lower unit is not the problem.

To get to all of upper shift stuff, you need to pull the powerhead off. Once the powerhead is off, you can see what you have. The mechanism is pretty straightforward. To take it apart, you need to tap out the roll pins on the hozonital shift shaft and unscrew the nut over the vertical shift rod gear. The gears may be indexed incorrectly or excessively worn. There are little plastic bushings under the moving surfaces which wear but I have never seen one worn through. If your shift gears are no good, I would find a donor motor as an old mid section will be a lot easier to find than a lower unit or powerhead. I am not positive, but any 9.8/7.5 from 73 to 85 will likely work. If somehow the indexing is wrong, I would put the lower unit back on and align the gears so that the action is correct.

Hope this helps.

Good luck and these are great little motors !

 

[fhafer]

Re: 1975 Merc 110 9.8hp shifter binding

Follow-up:

I just recently acquired this boat & motor. I saw the motor start, run and make way. I didn't run the motor myself because I had my own boat at the lake with my kids. I have a 12 foot jon boat.....this one was a 14 foot jon boat and large enough for me to take my whole family out. The 12 footer required someone to stay on the beach.

As I stated in my earlier post, I dropped the lower unit last night and the lower unit shifts properly. I got the upper shift linkage indexed correctly with the throttle; when in forward and reverse the throttle has full range of travel. In neuteral the throttle is blocked to the start-shift range.

This morning I tried to re-install the lower unit. I put the upper shift assembly in neuteral as well as the lower unit. They wouldn't mate. After two hours of push/pull/curse/inspect/push/pull ect I threw the upper shift assembly into forward and the lower unit in neuteral.........and they slid together with the push of a finger.

Now the motor is stuck in forward. When I started it was stuck in reverse. I'm thinking someone had the upper linkage apart and reassembled it 180 degrees out. Is this possible. I'm ready to follow the above recommendation and pull the powerhead, just hoping someone has had or seen this problem before.

The lower unit does not look like a swapped unit. Paint, scratches and fit all look to match the upper exhaust housing. Nothing obvious to point to a lower unit swap.

Any thoughts???!!

Thanks

 

[fhafer]

Re: 1975 Merc 110 9.8hp shifter binding

My lower unit and upper shift mechanism is 180 degrees out I think. On the upper end of both the upper vertical and lower vertical shift shafts I have an area without splines.......kind of an indexing flat spot. On the upper vertical shift shaft I can see this just below the lower cowling where the shaft enters the exhaust housing. With the upper shifter assembly in forward gear the flat spot on the upper vertical shift shaft is pointing directly aft (180 degrees). When I shift to neutral it rotates clockwise to the aft port quarter(225 ish degrees). When I continue thru to reverse the flat spot continues rotating clockwise to the port beam (270 degrees).

On the lower unit vertical shift shaft the flat spot is directly above the propeller (180 degrees) in reverse, rotating the shift shaft counter-clockwise the flat spot is pointed to the stbd aft quarter (135 is degrees) in neutral. Continuing to rotate the lower unit shift shaft counter-clockwise the flat spot on the lower unit shift shaft is pointed to the port beam (090 degrees) in forward.

I think something is 180 degrees out from where it's supposed to be......I just don't know what.

HELP!!

Thanks.

 

[fhafer]

Re: 1975 Merc 110 9.8hp shifter binding

Final update:

Went down to West Marine and bought a brand new four stroke Mercury 9.9

Problem solved.

Kidding!!!


I removed the carb, this gave me full access to the shift linkage. Removed all the upper shift linkage. Set the upper vertical shift shaft to neutral using the throttle stop detent as my fixed neutral point on the upper end.

Then I peered up the exhaust housing and saw that the splined coupling on the lower end of the upper shift shaft was aligned nearly perfectly in the neutral position.

I set the lower unit shift shaft to the neutral position and slid the lower unit up. After a little jiggling of the upper shift shaft the lower unit slid into position. I tightened the 9/16? and ?? nuts on the lower unit.

Next I assembled the horizontal shifter and set the detent spring in place; this helped keep the external shift handle from moving while I set the roll pin and tightened the nut on the other end of the shaft.

Lastly I reattached the carb, placed it in the test tank and fired it up. Ran just fine, water out the tell-tale and shifted to both reverse and forward perfectly.

What I found was the small gear on the end of the horizontal shift shaft (opposite the shift handle) was out 90 degrees. I match-marked everything with a SHARPIE before I took it apart.

I don?t know if this will be of value to anyone in the future??I hope so.

Best regards,
Fred

 

[8075mercury]

Re: 1975 Merc 110 9.8hp shifter binding

Glad to hear you got it fixed.

Unless your gears were worn and the teeth skipped, the only way I can imagine how it got out of sync is someone took it apart and put it back incorrectly as you said.

Using neutral as a reference point works. The factory manual suggests putting everything in forward when removing the lower unit and reinstalling. In forward the flat spot on the lower unit shift shaft faces aft.

Great motors ! (and they weigh a lot less than a 4 stroke 9.9hp!)

 

[Fallen001]

Re: 1975 Merc 110 9.8hp shifter binding

Thank You,

I think I have a similar problem ...


my merc 110 - 9.9 also is being "governed" while in Forward and doesn't throttle all the way up. It's being "blocked" by the shift linkage and the little plate that slides over to block the tiller arm/throttle control movement ...

Throttles up to fully open while in Neutral & reverse, but not forward ...


Just to verify, this isn't a lower unit problem? correct? just the plate in the upper unit is incorrectly positioned ?

 

[Fallen001]

Re: 1975 Merc 110 9.8hp shifter binding

Hello,

Update on my issues ...

I dropped the lower unit, made sure the rods were in correctly, and set the upper unit shift handle into forward ... I then slid the lower unit back into place and that solved the problem ....

I can now shift, with ease, into both forward & reverse and it starts up in neutral ...

All in all, it took me about 30 mins and my old Merc is a much happier beast !!


I don't think the lower unit was in correctly for at least two previous owners ... The motor hasn't been ran in years at it's full potential because the upper shift handle was misaligned with the lower unit and you couldn't open the throttle all the way when it was really in forward ...

great forum and good advice on here ...


now I'm searching on how to tune the idle screw correctly ...

 

[Greggsr219]

Re: 1975 Merc 110 9.8hp shifter binding

I have a very similar problem. 76 9.8. I just bought it used. After a carb cleaning got it started and noticed not water flowing. Installed a new water pump. Put both the lower unit and the shifter in forward and reinstalled lower unit. Now it is will not shift out of forward. It feels like it is binding, like it is not in "shift" position on the throttle.