Reverse lock assmebly adjustment procedure?

[rjb75]

I have a 1977 500/50, s/n 4805706. The hooks for reverse lock move maybe 1/2" when reverse is engaged from the controls, the hooks can be moved throughout their range of motion fairly freely by hand. The pushrod also seems to have a lot of play up and down. This did not work properly before I had the LU off yesterday to do a water pump so I don't think I did anything to affect its operation. I did not notice any damage to the reverse lock cam although I did not remove/reinstall for inspection :facepalm:

My water pump now pees like a champ so it's not all bad.

My question is, is there any other adjustment for this aside of the the nut on the pushrod right below the hook assembly? Any other parts to look at before I pull the LU again to check/replace the cam?

BTW, I do have a factory manual on order, just trying to get this done for today's trip on the water.

Also, I have read on this site that there is a newer steel replacement for the reverse lock cam but I cannot seem to find a part #. Would this be the cam made for same model year as mine but after the higher serial number break?

 

[ajgraz]

Re: Reverse lock assmebly adjustment procedure?

Are you saying that the hooks move some when reverse is engaged, but not enough to hook the bar securely? Are you at least going into the proper gears via the control box/shifter? (this will tell if the shift shafts were mated properly)

Bear in mind that the hooks are also supposed to engage the bar when in neutral...maybe the cam was reinstalled off by one spline? If you get no hook movement from F to N, and just a little movement from N to R, this may be your issue.

Assuming the cam is in right...those cams will develop a groove from the pushrod, which can cause the hooks not to move enough no matter how the nut is set. That happened on my old 1978 70hp; I fixed it by shimming under the cam with a couple of really big (I wanna say, 9/16" or 1/2"?) stainless flat washers.

(I was gonna replace the cam, but this has worked well for years now)

 

[rjb75]

Re: Reverse lock assmebly adjustment procedure?

Yes the engine shifts into forward and reverse properly. I left the unit in neutral before disassembly and did not touch the controls or shift shaft in the LU while working on the water pump. The PO did have some LU problems (I have receipts) so maybe he or the mechanic he had installed the cam in the wrong position. After reading in my crappy Seloc manual, I found the cam install instructions. I'll have to pull the LU again to check it I guess and I'll have some washers handy in case it's grooved up badly.

 

[hotrod53]

Re: Reverse lock assmebly adjustment procedure?

I have a '77 500 also, as ajgraz says, maybe the cam is off a tooth or so, it can be installed as many ways as the shaft has splines.

When I had my lower unit off, I was told that the plastic cams, or the plastic cams with metal inserts, should be discarded and replaced with all metal cams for the very reason that you describe, and they are relatively affordable, <$20.

Be sure that your clamp fingers move the full range and freely, they are known to bind. Being that you used neutral instead of FWD, I think you could be off a tooth or two without knowing. In my case, my lower unit was assembled improperly for 30 years and no one knew it!

 

[rjb75]

Re: Reverse lock assmebly adjustment procedure?

Thanks. Does anyone know what the part # for the all metal cam is? All I see when looking up parts by serial # are the discontinued plastic ones which I can pick up on ebay.

 

[rjb75]

Re: Reverse lock assmebly adjustment procedure?

Anyone out there that can help me to identify the all metal cam? Please?

 

[rjb75]

Re: Reverse lock assmebly adjustment procedure?

Finally pulled the LU and yes the cam was installed in the wrong position. The reverse lock works like a champ after installing it in the correct position.