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Alpha One Dogs

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edcourter

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My Alpha One driven by a Mercruiser 260 has slowly lost reverse, click,click,click under load. I have all the cables correct and 1/2 inch play in the cable that goes to outdrive from the engine top. Yesterday I had someone slowly move the helm control until the dogs started to rub when turning the prop by hand. I was turning in the driven direction so the dogs would rub but not hook the backcut. Both forward and reverse made initial contact with dogs an equal distance from the midpoint(neutral). When helm control was slowly pushed into forward the resistance increased progressively and at end of shift travel the prop would lock hard into dogs and not move when turned against the driven direction. This seems correct (dogs hooked)

When the helm control was slowly pushed into reverse the resistance also increased progressively and at the end of the shift travel the prop would turn with hand force and click/clunk in both directions. The helm control was held in the end of shift position. This seems like rounded dogs.

To My Question. Need I remove and disassemble the outdrive to check for something else that could cause these symptoms such as cables or linkage that I can get to and fix cheap, or, It can only be the drive dogs so get out the money. Thanks Ed
 
there are many reasons not just worn dogs. Remove the drive and check everything for looseness. Then check the upper brass shoe and the lower splined shaft for wear. Then make the jig to test the shift spool range.
Then and only then disassemble the lower unit
 
Thanks, I measured the rear cable play with the prop held hard in forward and got 1/2 inch play (9/16 is merc max) Wouldn't this indicate a good linkage through the leg? Also the initial contacts with the dogs both forward and reverse are dead symmetrical from neutral?
 
edcourter said:
Thanks, I measured the rear cable play with the prop held hard in forward and got 1/2 inch play (9/16 is merc max) Wouldn't this indicate a good linkage through the leg? Also the initial contacts with the dogs both forward and reverse are dead symmetrical from neutral?
Click to expand...

This is like which came first...... the Chicken or the Egg?

Yes..... while spinning the prop back-and-forth rapidly (in both directions), you are correct if you first consider establishing both FWD and REV "Dog Teeth" contact.
Absolute Neutral will then be at an equal distance from either contact!


Question:
If you were to spin the prop back-and-forth rapidly while the cable is moved in the REV engagement direction...... how much more cable travel do you have once passed the clicking sound and into what would otherwise be "full engagement" ?????
 
Once I just start to tap the dogs I have about 1/2 inch of rear cable movement to end of travel which should be full engagement. I have the same amount forward and reverse. I can get a precise number if needed, Boat is about a mile away. Thanks
 
start with the 6 inch dimension while in full fwd, attach plastic end, adjust brass barrel to match slot, and install cotter pin.
Shift into reverse, adjust stud for good reverse engagement
Test run.
If you cannot do this you have other issues with the shifting system
 
Thanks, Given that whether I replace it or repair it, I guess it still must come off. I will check the linkage, angular movement, couplings and shoe. The cable throws and stud adjustments are very close or exact. Thanks to all.
 
Sorry, The shift cable (engine to outdrive) when moved out of neutral will at some point cause the dogs to just make contact. At this point (forward and R) you can turn the prop either direction with just a slight clicking. At this point the same shift cable will move another .40 inch into what should be full engagement which is also the end of the cable travel. These are measured at the engine where the two cables come together. The other cable (engine to helm) moves a little more as it is farther out on the lever. Thanks again
 
on the lower shift cable push the plastic end in all the way while turning the prop CCW till locked ,this is full fwd.
put the control box in full fwd, full throttle , attach plastic end to stud and adjust brass barrel to fit slotted area,
you are now in full fwd gear, shift into reverse, adjust stud by raising it to get full rev gear.
report results
 
Sounds like some of my experiences with normal age & wear.

Something I've done that has worked for me a couple times was to adjust the shift
cables at the back so you get the most travel possible from the
one that goes on back into the outdrive housing.

The tolerances in them is so tight, there's not much extra travel built into the system.
You lose some travel as cables wear and stretch.
As that is happening, the clutch dogs are wearing some.
Between the two, you are losing cable & clutch travel
when you are really needing a little more of it.


.
 
I have about 1200 hrs. If I pull on the rear cable (engine to gears) at the engine, and hold it, I can still with enough force ratchet the dogs in both directions. Again I have the same travel both forward and reverse after my initial dog contact. Forward works well. If I can be 90% sure its the dogs I can just replace it without any inspection or diss-assembly. Its been adjusted very carefully.
 
You still dont understand how it works, If you push the cable end toward the stern all the way you go into fwd, it will lock turning the prop CCW and ratchet CW.
Pulling is going into reverse, If you cannot lock the prop CW then remove the drive and examine the arm for a missing roller or looseness. Mud,and other debris can get behind the shift slide and become compacted preventing full travel of the slide and prevent reverse from full engagement.
THEN PERFORM A SHIFT SPOOL CHECK http://www.boatfix.com/merc/Servmanl/6/6C1R3.PDF
If you can engage reverse with the splined shaft and the splined shaft rotates past straight the shift spool is worn .
 
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If this is like an outboard, you don't need a lot of 'push' to get forward to engage--it's spring loaded. Reverse requires fighting the spring pressure to engage, so biasing the adjustment towards reverse should fix the problem--if it's like an outboard.

Jeff
 
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