Shift interrupter switch not working/ activating too late.

[Pruno]

Hi all - finally got the boat in the water yesterday for the first time this season. As a result of haste and my own stupidity last fall I had to replace the lower shift cable this spring (among a few other items). I adjusted the the lower shift cable and the remote shift cable, then for posterity I did it one more time. Between having the manual and watching achris’ video a few times, I feel that I’ve done it correctly. However, boat in the water, it’s not shifting into neutral from either fwd or rev. I know the shift interrupter switch is a working switch, but it’s not engaging in the water. So today on the trailer I checked one more time.

Digging deeper I was able to determine that the shift interrupter will engage if the remote control is moved through the neutral position. So coming out of forward I would have to put it slightly into reverse, and out of reverse I’d have to put it slightly into forward to active the switch. I think that while in the water this was causing me to skip right over neutral and only go straight from fwd to rev and vice versa. It’s the newer style switch, so I don’t believe there is any adjustment I can make there.The only thing I found amiss is the remote shift cable “throw “ is measuring at 3 3/16”, maybe 3 1/4”, and I know this is out of spec

My question is, would the extra “throw” in the remote shift cable cause this problem? If so, is there any adjustment to be had, or am I looking at a new remote shift cable or new remote?
Everything I read and viewed about this problem points to the lower shift cable maybe something else I’m missing?

if it matters, I believe the remote to be a quicksilver 4000, alpha gen one drive, and the engine I’m unsure. The boat is new to me (and I to boating) and it’s not the original engine. There’s no s/n tag where it should be. What I do know is it a 4.3, the cover on the carb say thunderbolt V, vortec is stamped on the valve covers, and everything seems to match up with Merc manual 25.

 

[achris]

When you move roller 'b' 3mm away from the Vee notch, the switch should close.

 

[Pruno]

Thanks for the reply. I have the other style switch, the one in the right. The switch does close if I push in on the plunger. The title of my post may have been misleading, the switch itself is working, but the plate doesn’t move when I put the shift lever into neutral. In have to move the shift lever through neutral and into the opposite gear before the interrupter plate moves. And that’s from either Fwd or rev.

 

[achris]

Check that all pivot points are free to move, and well lubricated. The lever should move quite easily.

Chris.........

 

[Pruno]

Didn’t have too much time to work on it today. I checked all pivot points and everything seems to move freely. Went back over the adjustments again and found the lower shift cable has excess slop of 3/4”. I can see how the travel of the remote shift cable is being consumed by that excess play.
so tomorrow the drive will come off. I’m hopeful that somehow I just didn’t get the cable set into the shift guide all the way. I’ll also check for access travel in the shift spool. Is there anything else I should check?

 

[achris]

The drive is an Alpha One, so there are a few places to look.

1. The 'shoe' on the bottom of the upper shift shaft. If it's splayed a bit, that will add to the total slop. Give it a SLIGHT squeeze with pliers (or multi-grips) and make sure it's snug (not tight) on the intermediate shift shaft.
2. The roller on the lever at the top of the upper shift shaft can get some wear on it and lead to a flat spot on the roller. Check that there is very little clearance between the fingers of the shift slide and the roller, and that the roller isn't worn on one side
3. The end float on the shift slide on the lower shift cable can also add more slop. With your fingers, just move the slide very gently and feel any 'in-out' movement. More than about 0.1mm is too much. Remove the lock wire and very gently turn the set screw, then replace the lock wire. The slide must still be able to rotate freely on the core, but with as little end float as possible.
4. I have never seen it, but it's a possible place, and should be checked. Any movement in the splines between the intermediate shift shaft and the lower shift shaft...
5. If after checking 1 to 4 the slop is still there, the shift cable outer may be worn internally, meaning the inner core may have worn a groove inside, and each time the cable is moved one way then the other it has to move from the outside of the groove to the inside (or the other way if it's being pushed) and that increases the amount of travel you see at one end before the other end moves, 'slop'... Only way to fix that is a new shift cable.

Here's a diagram to show the places to check.... (Difficult to see, but the 'shift shaft' in the diagram consists of 3 sections, Upper, Intermediate and Lower, surprisingly enough. Upper to intermediate coupling is a 'shoe and foot' design, and intermediate to lower is splines.)

 

[Pruno]

Chris - you were spot on! And now the shift interrupter comes on just as the throttle lever is eased into the neutral detent. The major source of the slop was found in the shoe on the upper shift shaft. Not sure if the picture below will do it justice, but it was splayed quite a bit and bent. I was able to bring it back in with a touch more than a slight squeeze from a pair of pliers.
There was a flat spot on the roller too, but didn't seem to add too much to the overall excessive play. It looks like the only way to fix that would be to replace the shift lever that it is attached to.

 

[achris]

....
There was a flat spot on the roller too, but didn't seem to add too much to the overall excessive play. It looks like the only way to fix that would be to replace the shift lever that it is attached to.

Yes. The roller is part of that lever. Usually the screw holding the lever to the upper shift shaft is loctited in, and the best way to remove it is to hit the end of the lever from above. The lever breaks right along the screw line. Just lift out the 2 pieces and put the new lever in...

Well done on finding the splayed shoe. :thumb:

Chris...

 

[Pruno]

Good to know. It actually came out surprisingly easy. I had to take it off so I could get the shift shaft to the bench mounted de-splaying device. I hit it with some loctite during install. For now it will do, but I know where to look if this peeks its head out again..
Here's to ya!

Matt