74 Merc 650 motor lock

[mercurymang]

Just purchased a boat with the above motor. I have found that i cannot seem to lock the motor. There is a spring loaded pair of hooks that clamp down over a long dowel that I think should lock but it does not. Anyone have any idea what i am missing or how the locking mechanism is supposed to work?

 

[Maxz695]

Re: 74 Merc 650 motor lock

Revers cam lock only locks down when in revers. Try shifting into revers and see if it locks down If not the cam is more than likely shot and the lu would have to be removed to replace it, It is on the shifter shaft in the lower unit. although I took apart a 70 HP unit with pistons that did not have the cam for the cam lock on it. In any case I would think it should be there. If not someone may have removed it for whatever reason when doing the impellor which while your in there if you have to remove it would be a great ide to replace as well along with the lower unit oil seeing how you just got it

 

[mercurymang]

Re: 74 Merc 650 motor lock

I shifted into reverse and the motor still did not lock. I suppose i need to get hold of a parts diagram and find out how all that works. Thanks for the info.

 

[Maxz695]

Re: 74 Merc 650 motor lock

I,ll send a picture from ebay if I can find it to show you the part and breifly explain the function. http://www.ebay.com/itm/39021-Cam-R..._Accessories_Gear&hash=item43b2f6e7be&vxp=mtr The Hi dentent lifts the shaft which in turn pushes the clamps down on the pin in revers. It drops in neutal and fowrds to let the engine lift freely. This Cam sits on the lower shift shaft of the LU and must be put on correctly and the LU must be put up correctly for this to work correctly. The one in the picture looks kind of beat up. It,s not a very hard job if you have minimal machanical abilities

 

[mercurymang]

Re: 74 Merc 650 motor lock

This Cam sits on the lower shift shaft of the LU and must be put on correctly and the LU must be put up correctly for this to work correctly.

Thanks for the help Max. Are you saying that it must be installed correctly or that the motor must be configured correctly for it to work?

 

[Maxz695]

Re: 74 Merc 650 motor lock

when the lower unit gets dropped drop it with the shifter in neutral. The prop should spin freely in both directions when the shifter is in fowards the prop clicks (Ratchets) in one direction then locks in the other. When in reverse it locks in both directions. This will have to be confirmed when putting the LU back on to insure proper installment. The cam lock when dropped in the neutral position should be half way between the high spot (Dentent) and the lowest dentent. (The middile of the cam.) facing forwards to the front of the LU I,ll post a picture. View attachment 171812View attachment 171813View attachment 171814 This is my lower 70 HP unit. The shifter is in foward gear. The lowest part of the cam is facing fowards. If I where to turn the shift saft one Position to the left it would be in the neutral position with the middle of the cam facing forwards. This is where your going to have your shifter when taking it down and this is where you are going to put the middle of the cam when installing it. (Slides on the shifter shaft). As you can see that when the shaft gets put 1 more spot to the left in reverse the highspot of the cam faces fowards. This liftd the rod that goes up toe the lock down mechanism and clamps down on the tilt pin. If you have any problems or think maybe a wahser or spacer is missing as well just write back to the forum and someone can help you. Make sure you get the proper cam for your engine as there are differnt styles for particular engines. Your serial number would assist in finding the proper cam.

 

[Georgesalmon]

Re: 74 Merc 650 motor lock

It its power trim it may not have the reverse lock.

 

[Maxz695]

Re: 74 Merc 650 motor lock

That is true and if so leaking pistons or hoses bad pump with a lack of hydrolic fluid are the cause but whywould Mercury if the engine has power trim would it have the lock down clamps?the pin the shaft and leave off the cam just to save a few bucks? It should be ther anyway incase of trim failure

 

[mercurymang]

Re: 74 Merc 650 motor lock

Much thanks Max. I think the guy that I bought the motor from said he replaced the water pump impeller. Maybe he installed it back wrong? At any rate, I'm going to go drop the LU and have a look see. Also, can you tell what the purpose of the tab that's circled in red in the picture?

 

[Georgesalmon]

Re: 74 Merc 650 motor lock

Good question, I don't know the answer but my 1979 115 has the clamps even though it has power trim. But the reverse lock cam is not on the shift rod in the LU.

 

[Maxz695]

Re: 74 Merc 650 motor lock

View attachment 171818View attachment 171819View attachment 171820View attachment 171821That is for the manual lift lock. There is a bolt pin that goes there with a bracket that hold the engine up for trailering. I,ll take another picture soon. Theres my betsy LOL the other pictures should give you some idea how it goes. This is a 40 HP Midsection. I adapted for my 70 HP 1979

 

[mercurymang]

Re: 74 Merc 650 motor lock

I do not not have power trim (unfortunately). I was able to remove the LU and here's a picture of the cam position. I took the LU of with it in neutral. Seems to me that it may be off a hair but i'm curious as to what you think. BTW, Betsy looks nice.

 

[Maxz695]

Re: 74 Merc 650 motor lock

If this is in neutral the cam is in the wrong position. if the prop is spinning freely in both directions then it,s in neutral. if this holds true then remove the cam and put the center Half way point facing the front of the LU turn 1 notch to the Left. You have a square shaft mine has many positional points so it may be correct as it is. If the hi spot is directly fowards at that point put it back the way it was and then look up into the midsection and see if the lift shaft is in the center of the plastic guide. The guide may have fallen out when he redid the impellor and the shaft is not through the shaft hole where the cam can lift it. It should look like this View attachment 171826

 

[mercurymang]

Re: 74 Merc 650 motor lock

Ok, I'll go check it out and report back. BTW, now I fell stupid but you were right about the motor tilt lock. Mine is a little different but here's how it works:

 

[Maxz695]

Re: 74 Merc 650 motor lock

View attachment 171832There ya go!!! re read my last post Edit ..--->>> After re visiting your photo It appears that if you do move the cam one spot to the left it will be at the center point of the cam which would be the correct spot for the cam in neutral.

 

[mercurymang]

Re: 74 Merc 650 motor lock

After I made sure everything was line up and positioned as you stated, and after cleaning things up a bit, I re-installed the the came rotating it 90 degrees CC. After bolting it all up, voila, it worked. In forward and neutral, I am able to lift the motor to it's stow position, it neutral, the hooks lock so i am unable to lift it. I am extremely grateful to you. If you ever get out Fort Worth, Tx way, I'll buy you lunch Max.

 

[Maxz695]

Re: 74 Merc 650 motor lock

The hooks should not lock in neutral only reveres I believe. Maybe a mistype as you stated you can lift it properly in Fowards and Neutral. Just send papa johns Pizza lol

 

[mercurymang]

Re: 74 Merc 650 motor lock

Yes, I mistyped. The hooks are only locked in reverse. Shoot, If your willing to send me your address, I send one your way.
BTW, this is the second time iboats helped me out of a jam. iboats forum is the best boating forum on the internet when it comes to nuts and bolts and just good information.

thanks all.