reverse cam lock problem 70 hp mercury

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glastron fan

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I have a 1979 70 hp 3 cyl mercury outboard. my problem is that it won't let that reverse lock down on the bar clamp on the transom tilt pin when I shift into reverse and GENTLY try to back away from the dock The engine will jump up then I try to back it off & the motor slams down. I have just put in a new cam reverse lock & mew water pump etc. & checked the cam vs what the manual says it's right but there is an actuator rod that looks like it may be bent I dont know because if it was straight it would not make the angle to hit that rod at all. Does anybody know if there is an adjustment for this? thanks for your help

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Jaynen

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Re: reverse cam lock problem 70 hp mercury

I had this problem with my merc. The rod is supposed to be bent to make up that angle. You can spin that rod in and out to adjust how much it clamps around the tilt pin. But the hooks only lock on when in neutral or reverse not forward. So you have to make sure when you put the lower unit back on that the piece that pushes the bent rod up to lock it on is lined up on the splines of the shift shaft properly. When I put my lower unit back on I shifted everything to nuetral so I could make sure the piece was on at the right rotation. I have a 1974 merc 500 but I would imagine its close to the same. Sorry if my explanation is confusing.
 

glastron fan

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Re: reverse cam lock problem 70 hp mercury

Thank you for responding Jaynen I will fool around with it tommorrow I did put the control box in neutral before I mated the lower unit together. I was wondering what you were refering to as far as the upper splines for the reverse cam if I try to turn that little splined shaft in the lower unit where the cam is I cannot turn it there is a nut on that actuator rod that has threads but with that angle on the rod do you just keep on turning it out till you think it's enough & try to leave the angle the same? The other problem is that I cannot put the motor all the way down to check to see if the reverse lock will work with the boat on the trailer because the first roller sticks out too far against the lower unit in the down position. I guess I could try to dry slide the boat back far enough so I can see if it will lock when I shift it into reverse from the control box. any thoughts on this?
thanks again.

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Jaynen

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Re: reverse cam lock problem 70 hp mercury

The motor doesnt need to be in the down position to test the reverse lock. The part about the splines that I am refering to is if you take the lower unit off you will see the shift shaft. That shift shaft has splines that mate with the other shift shaft in the engine. But on the lower unit side you need to put the reverse lock cam on at the correct position on the splines so that when you are in nuetral or reverse the cam will be pushing the bent rod up causing the hooks to grab the tilt pin. If its in another other position it prolly wont work. I doubt you will have to spin the bent rod though, its probably in an okay position. Its only ment for fine tuning.
 

MassillonBuckeye

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Re: reverse cam lock problem 70 hp mercury

Related question: My reverse lock rod isn't connected to anything on the L/U. I think I'm missing a cam or something. Not really seeing much but a small part in a few parts diagrams. The rod doesn't look broken, just nothing attached to the bottom of it. Mine is a 7.5HP Merc
 

hotrod53

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Re: reverse cam lock problem 70 hp mercury

Since we're talking reverse locks, I have a '77 Merc 500 and my cam lock rod is missing. I have the brass clevis and the pin, we checked the cam on the L/U to be sure that it's in the correct position, but I have no rod.
I was wondering if my rod should be straight or curved? I know that it's a 5/16 - 24 thread and my clevis has an offset in it, maybe the rod is straight and I can make one?? Is the rod rounded on the bottom like an engine pushrod?

Massillion, there should be a round plastic cam that fits over the shifter shaft that has a ramp on it to push the cam lock up. This cam goes on in as many positions as the shifter shaft has grooves, that is why you have to put it on so that the ramp is at its highest when the L/U is in reverse.
 

FLATHEAD MAC

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Re: reverse cam lock problem 70 hp mercury

I too have a 74 500 that i have been working on the past few week off and on tryinr to get ready for the water . put it in buckeof water and started motor ran good but not "peeing". replaced waterpump , and found like many, that getting the shiftter RIGHT when going back together. after getting the shift right noticed the shift lock wasnt working. dropper LU "AGAIN" to find that the lock cam was not even there,went to local parts store, and they ware suprised that they had one in stock which was good for me. Got the cam installed ans lock wasnt locking, something still missing. cause rod would not stay on can. found that shift shaft /lockrod guide (pn# 93336 1)also missing ,lkuckly buddy had extra motor with LU off and thankfully the guide block was still there, hupefullty be up and locking next week:redface:
 

hotrod53

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Oct 16, 2009
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Re: reverse cam lock problem 70 hp mercury

I went thru most of that too before getting mine right. I replaced my reverse cam with a metal one, I was told that it would last much longer. They make a plastic one, a plastic one with metal inserts, and an all metal one. That lock rod guide was an issue with me too, you really couldn't determine which way it went and it was odd that it just slipped up in there.
 

GA_Boater

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I am trying to find the Right Position to put my reverse cam in. I fell out when I removed the Lower Unit to install a Water Pump and Impeller. Man this is Driving me CRAZY.

Start your own thread and tell us what Merc you have.

This is an old thread and now closed.
 

Kapt Bobby

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1979 Mercury 70hp Reverse Cam Install help

I have a 79 Merc 70hp outboard. I removed the Lower /Unit to install new water pump and Impeller. when I removed the L/U the reverse Cam few out. I have not found any Pictures or good info on how to reinstall the Reverse Cam. Can any one Help out with Pics or good advise On this Motor ?Does the Prop Spin Clock Wise to go Forward???? I need all of the HELP I can Get.
 
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