#%%^^# Reverse - 1963 Merc 1000

[bh357]

After having my l/u apart the better part of last year, I finally put my boat back in the water.<br />The past couple of years, I have been trying to sort out a reverse issue. Reverse was slipping when I gave the motor much throttle.<br />Late last year, I placed a small (~1/16") shim behind the cam follower, per guidance I received from a few people.<br />Yesterday, I was able to get reverse to engage solidly once. Now it just makes the ratcheting sound. Last year, it would engage, but would slip with any amount of throttle.<br /><br />Thanks.

 

[Laddies]

Re: #%%^^# Reverse - 1963 Merc 1000

Your upper shift shaft is about to break and is twisting instead of shifting the motor, If you shift that model engine into rev. just once with the engine not runnig you stand a 50/50 chance of twisting a brand new shaft

 

[bh357]

Re: #%%^^# Reverse - 1963 Merc 1000

Thanks Laddies.<br /><br />Are you trying to say that you think that the shaft is already bent? I've always been careful to only shift with the engine running, or at least have someone spinning the prop by hand when I shifted (engine off).<br />By upper shift shaft, do you mean the short 5" long section that slips over the lower shift shaft (the one in the l/u), or the shaft within the upper part of the leg?<br />Thanks.

 

[Laddies]

Re: #%%^^# Reverse - 1963 Merc 1000

The 5" extention sounds like part of a bay pattern kit ot make the engine a long shaft, they worked great. I think it is the upper part of the shaft thats twisted, it use to happen all the time. The best way to tell is to remove the carrier and prop shaft and look in at the shift cam with someone shifting the engine for you. I think you will find the the cam lobes don't lineup with the shift position

 

[Texasmark]

Re: #%%^^# Reverse - 1963 Merc 1000

What Laddies is talking about is the clutch dog in the lower unit that shuttles back and forth on the prop shaft (and shifts you thru the gears)has a triangular front (slip clutch) to engage F gear, but a square butt on it to engage R. It's a no brainer to shift from N to F with power off because of the spring loaded slip clutch front end.<br /><br />But if you want to shift into reverse, you put slight pressure on the shifter (till you feel any resitance) and slowly rotate the prop to get the gears to line up....then the shift lever will move on into R. You can feel it when you get it right....just slips right in.<br /><br />With the engine running, the reverse gear is driven by the driveshaft so it's rotating; not a problem for the gears to find the sweet spot and engage. <br /><br />Like he said if you force it, you are going to bend something.<br /><br />I had a well worn '65 Mercruiser I bought in the '80's and had a similar problem. Part of my problem was wear and the other part was the fact that I didn't have my remote control shift cables adjusted properly (centered between F-N-R). I think a shim would have helped me also by taking up some of the slack caused by wear.<br /><br />Course if the corners of the reverse gear/clutch dog are rounded, or if the spring in the front is weak, it could be another problem.<br />HTH <br /><br />Mark

 

[bh357]

Re: #%%^^# Reverse - 1963 Merc 1000

Thanks Laddies and Texasmark. I will see about pulling the carrier this Sunday; I should be able to get this out without actually dropping the L/U.<br /><br />Laddies, are you referring to a lateral bend in the shaft? I'm struggling to grasp how this would affect shifting, and what exactly I'm looking for when I have it open. Am I checking to see that the cam moves around smoothly, without any "wobble", or am I looking to be sure that the appropriate positions on the cam line up with where the follower will be.<br />My best "guess" would be the shaft is bent in such a manner that when rotated to the reverse position, not only does the cam turn, but it moves forward (away from reverse) by a bit. Is this correct?<br /><br />Lastly, do you think the shim could be causing any issues, or is it possibly helping things (I was able to get full engagement once).

 

[Laddies]

Re: #%%^^# Reverse - 1963 Merc 1000

The shim was a temperary fix, the shaft is not turning the cam in the lower unit to its highest or to the rear of the unit position becaust the shaft that turns it is twisted by improper sfifting or has rusted to the point that it has lost it's strenght, When you remove the carrier you should be able to look in the unit with a lite and have some one shift it and be able to see the problem the cam will not move to it's highest position and the neutral and forward detent slots will not be in the center of the hole for the prop shaft in fwd. gear when shifted in there gear positions at the shift box I hope you can understand all this babbling it's kind of hard to explain (much easier to show someone) Bob

 

[Laddies]

Re: #%%^^# Reverse - 1963 Merc 1000

Sorry for not getting this on the other post and I cannot seen to edit it But yes to the problem being that the cam is not turning far enough and all the shim did is help move the clutch dog further towards rev. and after you did that the shaft twisted some more, thats why I thing when you get it apart you will find out that it's rusted

 

[NEECAPRS]

Re: #%%^^# Reverse - 1963 Merc 1000

BH357,<br />Have you tried adjusting the linkage connection at the control input to get it to go into reverse?? The theory of the shaft being twisted explains your problem, but, it would take massive push on the control lever to twist it. It's hardened steel of about 5/16 dia at the root of the splines. I really doubt that you could twist it that way.<br /><br />BY THE WAY: Never play with the gear shift(like the kids would like to in the back yard) with the motor not running. Lower unit oil only gets splashed up into the aluminum bushing that the shift shaft goes through when the engine is running. If the bushing does not get oiled, the shaft will seize in it--surprisingly quickly!!

 

[bh357]

Re: #%%^^# Reverse - 1963 Merc 1000

I took the boat out again yesterday afternoon, and was able to get reverse ONCE. I backed away from the launch under my own power.

After that one time in reverse, it wouldn't shift into reverse again:|