Trouble Shifting into Reverse on 1998 25hp Mercury Tiller

Discussion in 'Outboard Maintenance' started by rkmurphy, Mar 22, 2009.

  1. rkmurphy

    rkmurphy Well-Known Member

    My Merc has the shift built into the handle. It shifts into and out of forward gear just fine but I've been having trouble shifting into reverse. If I can get it in reverse, it's fairly smooth and sometimes very smooth and it comes out of gear just fine. Otherwise, I can't get into reverse at all. My fiance's father who is a Merc mechanic said it's probably a linkage issue. Any theories?

    If it is a linkage issue, how do I fix this? Please be detailed as I'm new at this.
  2. TomFL

    TomFL Well-Known Member

    Here's how I would tackle this problem.

    Step one: Load motor into truck
    Step two: Drive to liquer store to pick up (cold) beer.
    Step three: Proceed to fiance's father's house.

    See how easy that was?  ;)


  3. rkmurphy

    rkmurphy Well-Known Member

    Haha I'm trying to avoid being out of a boat for another week.  Plus...can't try to get the big man to cover everything.

    His friend made it sound like it was something I could do on my own fairly easily...didn't go through any procedures, though.
  4. Brett

    Brett > PRO STAFF <

    Take the cowling off
    move the shift mechanism slowly
    watch what moves and where it moves
    look for the point where a mechanical clamping device has slipped
    it may be a set screw or bolt
    you'll be able to see the original location of the clamp
    by the scratches on the connecting part
    simple mechanical retrace-ing of shift activation
    plus you'll understand what is happening in the future
  5. Un-shore

    Un-shore Well-Known Member

    Just making sure here, are you talking about when the motor is running it has trouble shifting?
  6. rkmurphy

    rkmurphy Well-Known Member

    Thank you. I will see what I can do when I get it back...hopefully soon!

    While it is running AND when it is off.
  7. rkmurphy

    rkmurphy Well-Known Member

    Ok a little update. Got the boat back this weekend and took a look at the linkage. Everything looks fine and even with no slack in the lines.

    I discovered, however, that if the motor won't shift into reverse (this is, of course, while the motor is off) if I spin the prop a bit, I can then shift it. If it is shifting fine into reverse, I can fine a certain point while spinning the prop where it won't shift into reverse.

    Any new theories on the issue? Now I'm completely stumped...
  8. mark_gardner

    mark_gardner I Love!

    if you dont mind me asking.... when and where did you get this motor?
  9. marshman

    marshman just try to follow me....i dare ya...

    i may be late on this lil thread...

    but fwiw...

    ive always been told to never shift a motor into reverse while not running....not exactly sure what the reason is, but might be some advice worth researching...

    brett?? googlemiester?? can you confirm this or shoot this down??
  10. Brett

    Brett > PRO STAFF <

    I've heard the same about not shifting into reverse.
    Shifting into forward is ok. Anytime I wanted to shift into gear
    when the engine is not running it was always into forward.
    Basic rule of mechanics: If it don't go don't go.

    middle of page regarding trailering

    Never shift into reverse if engine is not running in section on Gear Shifting:
  11. rkmurphy

    rkmurphy Well-Known Member

    Wow...thanks guys. I had no idea. Is it bad if I've been doing it a lot lately? Could I have messed something up?

    I'm a little worried now because I really have been messing with it a lot...
  12. Brett

    Brett > PRO STAFF <

    Probably not, unless you have been forcing it.
    If it don't go easy, it don't go.

    If you can still shift gears you're probably ok.
    The last 200 feet to the dock ought to be at dead slow.
    I usually paddle the last 20 feet, it's easier than shifting
    in and out of gear, and avoids impact at warp speeds.

  13. rkmurphy

    rkmurphy Well-Known Member

    :( my most recent bragging spot post...
  14. Brett

    Brett > PRO STAFF <
  15. HaMm3r

    HaMm3r Well-Known Member

    I responded to your bragging thread post, but then read this. I don't know how well I can explain this, but if we were standing next to the motor I could show you in 20 seconds.

    Take a look at this picture...
    That's my merc lower unit, and the smaller silver rod on the right is the shift linkage rod. Yours should be similar. It runs from the lower unit up to under the cowling where it's connected to the shift mechanism with a pin. When the rod moves up, it shifts the lower unit into gear (I can't remember whether up is forward or reverse, but it doesn't matter for this discussion) and when it moves down, it first goes into neutral first and then into gear in the opposite direction. When you reinstall the lower unit, there are some pretty specific measurements for the length of that shift rod, and you're supposed to adjust it before you reassemble the motor.

    About halfway up the shift rod, there is an adjustable clamp that engages/disengages the trim lock lever when the shift rod moves up and down. When set correctly, this prevents the motor from flipping up while in reverse. You may have to loosen or remove this clamp to make any adjustments, so just be aware it's there.

    Now, I'm not saying this is your problem, but it could be. So, try to picture how the tiller handle rotates and adjusts the throttle accordingly. Well, the shift rod has to be adjusted so it matches the tiller's throttle adjustment. For example, shift rod in neutral position has to match throttle in idle position. If not, stuff like you're seeing will happen. Plus, if it's far enough out of adjustment, it may never move the shift rod far enough to engage reverse.

    If you remove the pin under the cowling and loosen the trim lock clamp, you may be able to twist the shift rod and adjust it. If you can't do it like that, then the lower unit may have to come off. At the very least, you should be able to remove the pin and push/pull the shift rod up and down manually, to make sure it shifts like it's supposed to.
  16. mark_gardner

    mark_gardner I Love!

    yo murphy, the reason i asked where and when you got this motor was because a while back i sold a similar motor to a guy and shortly afterwards i found a peice of linkage that i suspect fell off the motor while changing the plugs. i couldnt find his number to call him and tell him of my findings . just wondering if perhaps this could be the same motor???
  17. rkmurphy

    rkmurphy Well-Known Member

    I bought it from Bud Banks Marine in Lutz and the previous owner was there. He was a middle age heavy set guy with gray hair. He had a jon boat and a little blue skiff I remember.

    I'm gonna research this shift rod thing. Hopefully I can get this issue taken care of without any cost. The motor runs flawlessly (knock on wood) except for this issue. Keep the help coming guys...I need all the help I can get! I really appreciate everything so far.

    Update: I've dedicated 12:15-5:00pm tomorrow motor surgery time. I shot the guys at an email (they probably hate me because I always email them with questions and can never buy anything...maybe if I bought a motor from them in the first place I wouldn't have this problem!) and am awaiting some sort of reply. Hopefully they can help...they ALWAYS do. Great group of people over there. Motors are expensive but, even with no experience with them, I can guarantee they are worth every penny. They are definitely the experts in the area regarding small outboards. If I ever have to take my motor for repair, it will go there.

    Anyways...wish me luck and like I said, keep the help coming because I'll definitely need it.
  18. rkmurphy

    rkmurphy Well-Known Member

    Found a possible issue, although I don't know much about this.  If you look in the picture at the linkage I pointed out in blue, it is quite loose.  I can easily wiggle it around.  I'm not sure if this is a possible issue and needs to be tight or not but, it's just something I noticed.  Should I tighten it down?  Or is it fine a little loose?

    Could this even possibly be the cause?

  19. Brett

    Brett > PRO STAFF <

    That's the shift link, the elbow identifies it.
    The throttle link is the straight one next to it.
    Should be tight enough to transfer load,
    loose enough to not bind.
  20. rkmurphy

    rkmurphy Well-Known Member

    I guess it's fine then...hmmm...

    Well tracing the shift linkage I found where the connection is to the shift rod (#2).  I dunno if this is weird or not but, when I lifted up the lever that I labeled #1, reconnected it, and shot some WD-40 on it, it almost seemed to allow the me to shift into forward smoother.  Anyways...I'll mess with it more tomorrow.  Tired...

    I'm going to try to do more research as well.