2002 Nissan 4str 6hp shift linkage problem

JOSEPHC

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Jul 7, 2010
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2002 Nissan 4str 6hp . model 6A2-3R4-1
While removing the lower unit I forgot to release or seperate the shift rod from the cam rod.
I pulled the lower unit and it got hung up when seperated about 2"... I pushed up on the lower unit again. At this point I noticed the mistake.
The result is that with the lower unit removed I have tried to move the cam rod up and down by hand to get fwd, neutral, and reverse but the prop seems to be permantly engaged in both fwd & reverse...and I can rotate the cam rod around 30 degrees.......what kind of damage did I do. Thanks for your help.
 

pvanv

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Apr 20, 2008
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6,500
You pulled the cam rod out. The nylon cam rod bushing could be damaged, or the stopper could be bent, or the roll pin that joins the cam to the rod could be sheared... OR, you may just need to push the cam back down. Now that the cam is out of contact with the push rod, you may need some patience to get it back in, or you will need to release the prop shaft housing to get clearance to reinsert the cam.
 

JOSEPHC

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Jul 7, 2010
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thanks pvanv for your reply...the lower unit is off the motor right now....when I turn the prop by hand in fwd it rotates the drive shaft clockwise...when I turn the prop by hand in reverse it turns the drive shaft counter-clockwise....pushing the came rod in or out does not seem to change this...it seems to have lost the ability to change into fwd, neutral and reverse.....have only checked this by turning the prop by hand after pushing the cam rod in or out....
 

JOSEPHC

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more info on the problem....can only push the cam rod in about 1/4"...from the wear signs on the cam rod it looks like it typically should go in an additional 1/2"....
 

km1125

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Aug 10, 2016
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You can't be in forward and reverse at the same time... its just impossible. You're in forward, as the cam rod has been pulled up too far. You have to rotate it to get the bevels pointing toward the prop, then push it back down. I'd say pull it out (only one bolt), find out which side the bevels are on, then push it back down. As Paul says, it might take some work wiggling as it makes contact with the pushrod. By hand, it it pretty hard to push down into the neutral and then reverse positions, but you can do it. When going into reverse, you might have to rotate the prop a little to get the dogs to line up.
 

JOSEPHC

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thanks for the reply km1125.
how hard can one push on the cam rod to get it into neutral & reverse.
I am trying to figure out if I somehow detached the cam clutch from the cam rod.
If I remove the lower water pump housing, the cam rod & drive shaft as an assembley, does the bevel gear at the end of the drive shaft stay attached to the drive shaft.
With the above assembley removed could I fish out the detached cam clutch(if it is detached) from the top as I am trying to avoid having to remove the prop shaft housing.
I am trying to visual how the cam clutch ineracts with the push rod...is the cam clutch stepped where it bears against the push rod.
Thanks again for the help.
 

JOSEPHC

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I tried again pushing down harder on the cam rod and it worked.....I can now move it into neutral & reverse ....thank you pvanv & km1125 for your help and advice for it made all the difference....
 

km1125

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Glad you got it figured out. I'm not sure if this helps, but this diagram might help explain the interaction of cam and pushrod:

cam_and_pushrod.jpg
 

JOSEPHC

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Jul 7, 2010
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thanks for the sketch, km1125....it shows clearly how it works....I assume the bottom notch is for fwd, which could allow the cam clutch to slip off the push rod if the cam rod is pulled up too much....
 

km1125

Chief Petty Officer
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Aug 10, 2016
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496
thanks for the sketch, km1125....it shows clearly how it works....I assume the bottom notch is for fwd, which could allow the cam clutch to slip off the push rod if the cam rod is pulled up too much....

You are exactly right. And once pulled up past that point, then you can see how it can rotate and be hard/impossible to push back down. It would seem like if the parts were machined appropriately then it wouldn't be able to do either... be pulled up too far, or be able to rotate out of position.
 
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