oops...

murphylaw

Cadet
Joined
Apr 3, 2012
Messages
17
Here is another impeller thread. 1996 Force 120hp. Put the lower unit back on, in foward just like it came out. Slid back in fine. Tightened everything down. shifted into neutral okay. For some stupid reason I thought to try reverse. Was noticably tight but gave it just alittle more effort and "SNAP"! Well I took it all apart and the shift shaft is okay, but it appears to have sheared the dogs or whatever the lower unit shift shaft connects to way down low. Can I pull the prop off and slide all the guts out of the lower unit w/out making more problems. I guess the damage is done and I don't see any other solution. The shift shaft turns freely in the lower unit, and I slid it out and no damage to the shift shaft. It is still in foward and is engaged properly but have no use for a boat that only has foward gear. New boat to me. I've gone out twice w/ the boat, no problems but wanted the piece of mind knowing it has a new impeller for the weekend. Now I might be staying home :(
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,927
Re: oops...

Those things are really hard to break.
The dog would be almost impossible to break by shifting.
How about a few pics??
 

murphylaw

Cadet
Joined
Apr 3, 2012
Messages
17
Re: oops...

Sorry no pics. Going to dive in and hopefully someone local will have the parts I need. I really didn't think I gave it too much effort but more than normal. Not sure if it is what links the shaft to the dogs but it is diffenatly (sp) sheared somewhere. Please help!!!
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: oops...

Oh Boy! Big job just to see what is wrong.. At this point you have no choice but to disassemble the lower unit. With a little luck, you MAY be able to pull out reverse gear, drive dog clutch, and prop shaft and see what is wrong. However, Merc used a detent in gear and I don't know the particulars of that lower unit. It may be like OMC with a spring loaded ball in the propshaft at the dog clutch.

If you can not see the problem by pulling the prop shaft you will need to completely disassemble the lower unit. The pinion is in the way of the forward gear so you must remove both the forward gear and pinion to get to the front.
 

murphylaw

Cadet
Joined
Apr 3, 2012
Messages
17
Re: oops...

Good news is nothing was broken. The cam went past reverse and got into an interlock position. Took it all apart, lined the cam up w/ the spring loaded detent that goes through the propshaft. Reassembeled everything and took a vice grip to the shift shaft. Foward, Neutral, Reverse. I felt relieved and proud I could tackle something like this. I always feel better operating something I can picture in my head what exactly is happening. And what a simple, yet complex idea in a lower unit. Hardest part was getting the pinion gear off. Red locktight on the pinion nut. So last night I reinstalled the lower unit, in foward gear, double checked splines on shift shaft. Tighten everything down. No change. shift into neutral, stuck in foward. So I know what is going to happen next, I go alittle further and click it into reverse and "SNAP" I now know what is happening, but how? once it goes too far like I just did (again) how is it possible that I can turn the cam too far w/out even leaving foward gear? I know now to just turn the cam around to the start of the profile. DO NOT EVER TAKE THE SHIFT SHAFT OUT UNLESS YOU WANT TO SEE THE INSIDE OF YOUR LOWER UNIT! If you do the cam falls off the shift shaft and ruin your day. I will get some pics next time but not today. Happy Fathers Day!
 

murphylaw

Cadet
Joined
Apr 3, 2012
Messages
17
Re: oops...

Great day out in bro-in-law's pontoon. 15 people and very windy. kindof glad I didn't have my boat out. I respectfully disagree w/ other threads that putting your boat in foward before pulling the lower unit is advised. I lowered the unit in neutral, took a vice grip to the shift shaft and turned it all the way around to the beginning of the cam profile. clicked the lower unit into neutral and reinstalled. I do believe it is fixed. I have all gears. After work some night I will get it out and make sure. Thanks Frank, I always see very informitive (sp?) replies from you on multipule issues.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,927
Re: oops...

The reason I leave it in forward is while reinstalling the lower,you might need to rotate the prop to align the splines.
When it's going up as you turn it,it will usually slide right in and you know the alignment is right without dropping it again and making sure where the stuff aligns.
 

murphylaw

Cadet
Joined
Apr 3, 2012
Messages
17
Re: oops...

Or just put your hand on the flywheel and turn it that way like I did. Its fixed and I'm happy!
 
Top