2012 40 HP 3 Cylinder EFI Lower Unit Clutch Dog/Cross Pin Assy

[robm1]

Hello All,
I've gained excellent knowledge throughout this sight and wish to thank all who've helped.

I'm currently working on a 2012 Merc 40 3cyl EFI S/N 1C192900 lower unit and have a question about 17-8m0091340 ( spring/pin kit ) installation procedure which has superseded cross pin 8M0009287. The spring, washer and cross pin are different ( shorter spring, washer replaced by plastic extruded pin, cross pin no longer has flat face fore and aft) and upon installation there is very little to no discernable spring pressure either way upon the clutch dog. Mercury tech didn't have an answer as to why at their helpline. I thought these lowers normally have spring compression force towards forward gear. Will this cause shifting issues? Anyone have any thoughts?

Thank you all for your knowledge and help.

 

[Texasmark]

Hello All,
I've gained excellent knowledge throughout this sight and wish to thank all who've helped.

I'm currently working on a 2012 Merc 40 3cyl EFI S/N 1C192900 lower unit and have a question about 17-8m0091340 ( spring/pin kit ) installation procedure which has superseded cross pin 8M0009287. The spring, washer and cross pin are different ( shorter spring, washer replaced by plastic extruded pin, cross pin no longer has flat face fore and aft) and upon installation there is very little to no discernable spring pressure either way upon the clutch dog. Mercury tech didn't have an answer as to why at their helpline. I thought these lowers normally have spring compression force towards forward gear. Will this cause shifting issues? Anyone have any thoughts?

Thank you all for your knowledge and help.

The shift cam that puts pressure on the pointed cam follower on front of the prop shaft is in the smallest radius position (least force) in the F position allowing the spring to extend the most and force the clutch dog to rest in the rear of the F gear.

N is the medium radius and pushes the cam follower to the rear causing the dog to position itself between F and R .

R is the largest radius and puts max force on the dog forcing it into the rear of R gear.

What you can do is to put the LU in a vise on the work bench, and install a sample of what you think is correct. Then grasp the splined shift shaft or slide the prop on for testing and move it (the shift shaft) through FNR positions while testing the reaction of the prop. If you get it where each position produces the desired result then I'd say you have a workable assembly, regardless of the components it took to get there.

Remember that F has the overrun clutch so CCW rotation of prop is the locked position and CW skips over the sawtooth....the overrun position.
R, having vertical sides will lock in both directions where N spins freely.

 

[Faztbullet]

Check to see if you missed the hole in rod. Goes plastic in shaft, spring compress rod slightly to line up hole in dog. This is not a preload prop shaft but uses desmotronic shifting like bigger motors. Kit is to take some force off shifting process.

 

[robm1]

Thanks for the help guys. I figured that it was correct with the lightened spring compression, but I wanted to be sure before putting it back together.

 

[RowanCarter]

The shift cam that puts pressure on the pointed cam follower on front of the prop shaft is in the smallest radius position (least force) in the F position allowing the spring to extend the most and force the clutch dog to rest in the rear of the F gear.

N is the medium radius and pushes the cam follower to the rear causing the dog to position itself between F and R .

R is the largest radius and puts max force on the dog forcing it into the rear of R gear.

What you can do is to put the LU in a vise on the work bench, and install a sample of what you think is correct. Then grasp the splined shift shaft or slide the prop on for testing and move it (the shift shaft) through FNR positions while testing the reaction of the prop. If you get it where each position produces the desired result then I'd say you have a workable assembly, regardless of the components it took to get there.

Remember that F has the overrun clutch so CCW rotation of prop is the locked position and CW skips over the sawtooth....the overrun position.
R, having vertical sides will lock in both directions where N spins freely.


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Hello, I have a question regarding this. Can I ask here or should start my own thread? I am sorry for jumping on someone else post.