Mercruiser Reverse Shift Cable Adjustment?

auscarter12

Seaman
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Jun 19, 2015
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Okay iBoats family, another issue with my boat.

I had the lower shift cable replaced 3 months ago to my Pre-Alpha Inline 6 (Mercruiser 165) boat. It worked fine and shifted into and out of reverse as it should after replacement of the cable. The boat has been out maybe half a dozen times, and I rarely use reverse gear to begin with, but it's nice to have in some situations (docking, mouring, etc.)

My problem is now it is giving me trouble going into reverse. The motor goes into forward gear just fine. I have tried adjusting the lower shift cable both up and down in the adjusting slot of the shift bracket to no avail. Before adjustment, the gears were just grinding but would never fully engage. To me it sounds like the teeth of the clutch are grinding, but it isn't enough to fully engage reverse gears. If I adjust it too far one way or the other, the neutral kill switch kills the motor before it can ever go into reverse. Reverse can be engaged if someone pushes on the shift bracket manually.

So my question: Is the adjustment barrel for the lower shift cable something I should consider adjusting as well? Maybe one turn at a time? I know the adjustment of the barrel is mainly for engaging forward gear, but with having no luck adjusting the reverse cable in the adjusting slot, I'm not sure where else to turn. I would find it hard to believe that the cable is busted seeing as it was just installed a few months ago and the boat has never seen any harsh conditions or harsh driving. Is it possible that the cable has stretched slightly after being "worn in"? I am not sure where else to look. My last resort is pulling the drive to check the condition of the cable.

I have attached an image of what my shift bracket set-up looks like. I believe it is the same as an Alpha set up.
 

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auscarter12

Seaman
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Jun 19, 2015
Messages
59
Just remembered this little tid-bit. My Shifter is a quicksilver aftermarket shifter, not original to the boat. Reverse gear did not start giving me trouble until i greased up and freed up the "throttle only" button on the shifter. It was seized up. I never removed the shifter box, but could this possible be the culprit? Maybe an adjustment needs to be made at the Shifter Box instead of at the back at the shift bracket?
 

Fishermark

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Oct 19, 2003
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If the cable operates smoothly and will go into gear by hand, I would suggest double checking your initial adjustment. You have already tried moving the adjustment in the slot. Next step will be to test the shift spool. Here's a link to do that.
 

auscarter12

Seaman
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Jun 19, 2015
Messages
59
I checked the adjustment of the shift cable (it was previously adjusted by my mechanic, not myself). And the brass barrel was not adjusted to the appropriate 5 7/8 inches away from the end of the cable as it is stated in my manual. Tried getting it to shift into reverse with no luck. So I increased the measurement to 6 inches (in 1973 they changed the design and I'm not exactly sure what model outdrive I have). 6 inches still did not work. I adjusted the brass barrel and the adjusting stud out as far as I could get them and it STILL will not lock into gear. So my assumption is that the shift cable is shot. if I enter reverse gear very very slowly I can get it to lock up enough to hold, but that's the only way.
 

alldodge

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I checked the adjustment of the shift cable (it was previously adjusted by my mechanic, not myself). And the brass barrel was not adjusted to the appropriate 5 7/8 inches away from the end of the cable as it is stated in my manual. Tried getting it to shift into reverse with no luck. So I increased the measurement to 6 inches (in 1973 they changed the design and I'm not exactly sure what model outdrive I have). 6 inches still did not work. I adjusted the brass barrel and the adjusting stud out as far as I could get them and it STILL will not lock into gear. So my assumption is that the shift cable is shot. if I enter reverse gear very very slowly I can get it to lock up enough to hold, but that's the only way.

Lower shift cable replaced 3 months ago and adjusting the barrel that far and still cannot get it into revers, I think there is something else going on other then the cable. A shifter issue or maybe in the outdrive. Check the shift foot and cable connection
 

auscarter12

Seaman
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Jun 19, 2015
Messages
59
AllDodge By Shift foot and cable connection are you referring to the cable attachment at the shifter box up front? Like I said, I did not start having this issue until i freed up the Throttle Only button on the shifter. But all I did to free it up was use some WD-40 and let it sit - I did not take anything apart. Maybe I need to remove it and check it.
 

alldodge

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AllDodge By Shift foot and cable connection are you referring to the cable attachment at the shifter box up front?
No, this would be at the drive where the cable connects

Like I said, I did not start having this issue until i freed up the Throttle Only button on the shifter. But all I did to free it up was use some WD-40 and let it sit - I did not take anything apart. Maybe I need to remove it and check it.
Maybe the trouble is in your throttle handle, you should be getting the same amount of shift movement forward as reverse.
 
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auscarter12

Seaman
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Jun 19, 2015
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My next course of action will be to remove the shift box and inspect the cable attachment inside.
 

Fishermark

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Before you remove the shifter (if it is not already too late) - simply disconnect the control cable in the engine compartment. (The cable coming from the shifter). With it disconnected measure how much travel you are getting from the cable itself when shifting into reverse and again into forward gear.
 

auscarter12

Seaman
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Jun 19, 2015
Messages
59
Fishermark Yes, I am going to completely readjust the cables, but keep the old adjustment in mind in case i have to readjust it back to the previous set up.
 

Fishermark

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Just to be clear - I am not simply suggesting checking the adjustment of the shift cable. The shift cable is the cable that goes from the shifter plate in the engine compartment to down to the outdrive. That DOES need to be adjusted correctly, yes.

But the cable I am talking about checking is the CONTROL cable. This is the cable that goes from the shifter to the shift plate. There is not normally any adjustment that needs to be done to this cable. But since you did something to the shifter, I am suggesting checking the travel of this cable.

Just want to be clear on the shift cable - vs - the control cable.
 
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