Mark 58 - have I destroyed my shift cam?

new2mercs

Seaman Apprentice
Joined
Aug 3, 2009
Messages
33
Tried to reassemble my gear housing to the driveshaft housing the other day after replacing the water pump impeller, and had some difficulty getting it to mate up all the way... the driveshaft splines were engaged, but the shift shaft seemed balky.

Being an idiot and assuming that I hadn't disturbed the shift lever position, I tried to pull it together with the mounting nuts: It got _real_ difficult when it got about 1/4 inch from the housings mating together so I stopped. At that point, the shift lever was jammed and wouldn't move.

I noticed in the service manual that the shift shaft is supposed to stay with the gear housing, but mine didn't. I can't tell for sure whether this shift shaft is one piece from gear housing to shift lever, but if it isn't, I must've jammed it into the tilt-lock really well... I can't pull it out.

I made a tool to try to mate into the splines in the shift cam, but can barely feel them, and can't get a purchase to turn the cam. Could I have damaged the cam somehow? The splines on the shift shaft don't look chewed up at all.

If it matters, I think this is a long-shaft motor.

Thanks for any thoughts... .
 

timmeraw

Petty Officer 1st Class
Joined
Jun 10, 2008
Messages
258
Re: Mark 58 - have I destroyed my shift cam?

I did the same thing one of the first few times I reinstalled the lower unit on my old Merc 300. I had to use a bar to get it set back down as it was so jammed in under the carb. Just be patient when reinstalling after you get the bolts started ...with the shift cable detached from the shift lever...put it near the position/gear it was in when you removed it....and wiggle it a bit with your hand and you continue to tight the bolts on the foot. As it moves closer together there will be less and less play in the shift lever arm and eventually none. If it begins to bind stop and start all over again.
 

new2mercs

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Messages
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Re: Mark 58 - have I destroyed my shift cam?

I did the same thing one of the first few times I reinstalled the lower unit on my old Merc 300. I had to use a bar to get it set back down as it was so jammed in under the carb.

Thanks timmeraw,

So if I'm understanding correctly, the shaft is splined or pressed into the lever in the bottom cowl and I might have simply forced it up through the lever? (I haven't been able to find a clear picture or diagram in the service manual, and can't see too well past the mag and voltage regulator... .)
 

new2mercs

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Aug 3, 2009
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33
Re: Mark 58 - have I destroyed my shift cam?

Thanks timmeraw,

So if I'm understanding correctly, the shaft is splined or pressed into the lever in the bottom cowl and I might have simply forced it up through the lever? (I haven't been able to find a clear picture or diagram in the service manual, and can't see too well past the mag and voltage regulator... .)

Following up on my own question for posterity, the lever appears to be pressed on to the shaft -- at least I don't see any pins, and the service manual doesn't show any further disassembly of the top end of the upper shaft.

As for disassembly of the lower shaft from the upper, it took a big pair of vice-gripes, a 16-oz ball-peen hammer, and an acetylene torch. I finally figured out that I could get the flame from a 00 tip onto the splined area of the upper shaft in between the tilt-lock cams when the shift lever was in forward. (Being very careful of course not to melt the bronze cams...) After some whanging on the vice-gripes clamped to the lower shaft in what I hope was a non-bushing-contact area, it finally came loose. I cleaned the scuffs from the vice-grips up on the lathe.

Unfortunately, I still can't get the thing to engage in the shift cam splines. I think that I either damaged them earlier, or the missing snap ring is in pieces and blocking the splines. Looks like I'll have to completely disassemble the gear housing... .
 

new2mercs

Seaman Apprentice
Joined
Aug 3, 2009
Messages
33
Re: Mark 58 - have I destroyed my shift cam?

Again following up my own post in case someone else is searching for info on this issue, the following thread was invaluable:
http://forums.iboats.com/showthread.php?t=264376

My trouble turned out to be a bit worse than just having the shift cam move: the cam follower had also come out of the prop shaft, so even when I got the cam located and the shift shaft reinserted, the cam would rotate 360 degrees. Had to pull the prop shaft and reinstall the follower, then relocate the cam. Seems happy now: If the engine runs I'll install new seals later!
 
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