Lower unit removed...now with PICS

[Jason280]

I pulled the lower unit on my mid 90's Force 90 HP, trying to figure out why it will not go into neutral or reverse. Right now, the prop ratchets when turned clockwise, and I cannot find a free spin while turning the forward/reverse shift shaft. I can spin the shift shaft all day long, and it doesn't seem to be doing anything with regards to shifting gears from F/N/R. I've tried rotating both ways, with no luck. Should I "feel" anything when I rotate the F/N/R shaft? Also, should I be able to pull the shift shaft out of the lower unit? I can pull the shaft out of the lower until, and feel it "drop" into what feels like the proper position in the lower gear box. However, I cant get it to do anything once its back in...

 

[OldNBold51]

Re: Lower unit removed, can't find F/N/R with the shaft

Re: Lower unit removed, can't find F/N/R with the shaft

I pulled the lower unit on my mid 90's Force 90 HP, trying to figure out why it will not go into neutral or reverse. Right now, the prop ratchets when turned clockwise, and I cannot find a free spin while turning the forward/reverse shift shaft. I can spin the shift shaft all day long, and it doesn't seem to be doing anything with regards to shifting gears from F/N/R. I've tried rotating both ways, with no luck. Should I "feel" anything when I rotate the F/N/R shaft? Also, should I be able to pull the shift shaft out of the lower unit? I can pull the shaft out of the lower until, and feel it "drop" into what feels like the proper position in the lower gear box. However, I cant get it to do anything once its back in...

If your shift shaft is like my 89 125, the shift shaft is threaded into the shift linkage. TAke the cover off the top of the lower unit and look down to where the shift rod connects. You really need to be looking at a schematic of the shift mechanism so you can get a better idea of how this thing shifts.

 

[Jason280]

Re: Lower unit removed, can't find F/N/R with the shaft

Re: Lower unit removed, can't find F/N/R with the shaft

I'll have to take the cover off to look into the lower portion. I can tell you that both ends of the shaft are splined, and can't tell what is would thread into.

I may have to pull the entire prop shaft and gears to look at the clutch. I have found a few diagrams online, but I can't tell which motor I have. I believe its a '96, as that is how the gas tank is marked. However, the one of the carbs is date stamped '94, so I don't know.

Is it possible to look up the engine based on the serial number?

Also, I found the following comment online:

These engines were produced with Mercury lower units in the beginning, gradually becoming mostly Mercury motors with Force powerheads by the time they were discontinued for the 1996 model year

If I do require parts for the lower, specifically for getting the F/N/R fixed, will I be able to cross reference Mercury lowers and use Mercury parts?

 

[Jason280]

Re: Lower unit removed, can't find F/N/R with the shaft

Re: Lower unit removed, can't find F/N/R with the shaft

OK, I was able to remove the prop shaft:

Now, going by this link, it looks like everything is correct.

http://www.crowleymarine.com/mercury-outboard/parts/2013_20.cfm

However, I am not sure about parts 5, 6, & 7, as I have not been able to get the rearmost gear out. It is blocked by the drive shaft, which I have not been able to remove. I am not sure whether it just pops out, or if it will require a puller. Also, will I need to remove the gear pinion prior to removing the drive shaft?

Also, when I pulled the prop shaft assembly out, I found these two parts:

It looks like these are part of the follower kit-cam (#9). However, with the drive shaft in place, I cant pull the rear assembly. Hopefully the other parts are still somewhere in the lower, I really don't know at this time...

 

[Frank Acampora]

Re: Lower unit removed...now with PICS

That's the mercury designed lower unit and it is different than earlier Force engine lower units, specifically, before 1994.

It will not go into neutral because the spring that preloads the clutch has the clutch pushed into forward position. As per below, you are missing a couple of pieces to push the clutch back into neutral and reverse.

The shift shaft is splined on both ends and yes, you can pull it out of the lower unit. It rotates to engage gears and one of your photos shows the shaft and detent ball. Yes, you are missing a part or two, probably a small spring.

To remove the forward gear, you must remove the pinion gear. Shop procedure is to put a socket on the nut and pad the wrench where it hits the case. Then you turn the shaft to break free the nut--this won't be easy. The pinion will be on a splined taper which will "lock" and must be broken free. then the shaft will pull out. Carefull--there are loose rollers at the bottom of the shaft.

When reassembling, the pinion nut is usually replaced with new, and torqued. I don't remember the value, but it will be up around 80-90 foot pounds.

Parts 5, 6, and 7, are the forward gear and bearing, cup, and shim. They are still in your lower unit.

Don't lose or damage the shims under the upper tapered roller bearing. They are critical to set backlash and I think they are no longer available

 

[Jason280]

Re: Lower unit removed...now with PICS

The pinion will be on a splined taper which will "lock" and must be broken free. then the shaft will pull out

That's where I am stuck now. I've gotten the pinion nut off, but haven't been able to get the drive shaft out yet Any suggestions?

 

[Jason280]

Re: Lower unit removed...now with PICS

OK, drive shaft is out. All it took was a solid whack from a hammer to the side of the shaft, and it came right out. Got to give thanks to Todd @ Twin Bridges Marina, as he made it look simple!

Anyway, the follower kit-cam was simply out of position, and I found all 3 of the .219" balls that go with the cam. The cam mates in with the shift shaft splines, but I cannot figure out where the three balls go. Any ideas?