Merc reverse lock linkage 1977 50 hp

" I have a 1977 Merc 50 hp. I installed a new reverse lock cam on the shift shaft when I had the lower unit off to replace the water pump. The old cam was plastic and had one corner worn down pretty bad. The new cam looks like aluminum.

I put the lower unit back on, and it shifts into forward just fine, but is slow about engaging the reverse gear (I can hear it grinding) and does not appear to engage the reverse locking bar on the motor mount. The motor kicks up if I rev it up in reverse.

Does it just need adjustment of the shift linkage, or did I do something wrong when I installed the new reverse lock cam? The Merc service manual just says to make sure the shift shaft is in neutral and the top edge of the cam is pointing forward, when bolting the lower unit back up, which I did.

Once again, thanks in advance.

870xprs "

Re: Merc reverse lock linkage

Every outboard that I have ever used had some amount of grinding when going into reverse. Unless you have had this engine for a while and now the gringing is worse than it used to be, maybe its normal. Just make sure your RPMs are as low as possible when putting it in reverse. If you have ever seen how a lower unit goes into reverse, it cant help but grind. As far as the reverse lock engaging, it can only be that the cam is off by a tooth or so, of the shart needs wound out. That cam can go on as many different ways as there are notches in the shift shaft.


BTW, I am working oa '77 Merc 500 Thunderbolt and I am missing my reverse lockout shaft, I see that you worked on yours. I have the clevis and the pin but no shaft. Can you tell me if it is straight or curved? How long is it? Is the end just rounded or does it look like the head of a nail?