Mercury 125 cable jamming/not going WOT

[preston398]

Okay so I have a 2002 Mercury 125 2 stroke. I got this boat about 2 months ago and have been fixing all the rigged things on it and tuning it up. Didn't run quite right when I got it but I have slowly replaced parts/cleaned everything and have it running pretty good right now. When I got the boat it would run 44 WOT, not sure on RPM's as the tach was broken.
In the process of finding stuff that was wrong I readjusted all the synchronization and linkages back to factory settings, they were way off to start.
Now I can actuate the throttle by hand and it stops at fully closed and when the cam is fully depressed the shutters are all level.

My issue is that once the throttle cable is connected it will actuate the shutters to about 3/4 of the way open before it binds. Now the picture I attached shows what is binding as the boat is an hour away and I didnt take a picture of it specifically. The black piece that slides in RED makes contact with the BLUE piece that locks into the bracket on the motor and stops the throttle from advancing anymore.

I have tried adjusting multiple things to get it right but not sure if this is the wrong cable or maybe it is an aftermarket cable that the slide piece is just slightly to long?
Before I made adjustments the previous mechanic had the cam adjusted way out of wack so it would go full throttle but it did it very abruptly and you did not have very good control over the midrange.

 

[preston398]

I know this issue has come up before with people, I saw another thread on it but it never stated what was causing the issue.
I'm sure other people have ran into this as well.

 

[SingleShot]

Not sure if this will help but here are some pages from the shop manual for that motor. I have a 2002 125 merc so I may be able to get pictures of mine for reference.
I believe the item in blue should have some adjustment to it. I hope the attachments will help.

JK

 

[preston398]

Thanks man, I have the shop manual. I know the part is blue is adjustable but that is not the issue.
Even if you adjust the round piece in blue out to make the actual actuator longer when the motor goes to full throttle it would still get stuck.
The piece in red will jam on the mount that the blue piece goes into before the butterflies open all the way.

Also, I have the blue adjustment adjusted according to the manual. When at the idle stop it goes on with a slight preload against the throttle arm. If I adjusted it any more out it would not go on the arm or if I adjusted it in it would not be at idle.

If the actuator in red was slightly shorter, maybe a 1/4 of an in. Then the issue would go away. Thinking about just trimming it and seeing what happens.

It's kind of a hard thing to explain but i'll take more pics of it once I go work on it this weekend.

 

[SingleShot]

I took some pictures of my linkage with a ruler for reference. IMG_1512 is with the throttle in neutral or Idle. IMG_1515 is with the throttle full. Hopefully you will be able to get an Idea if your cable and control geometry is correct. It appears that 1" of cable travel results in idle to full throttle. Hope this helps.

JK

 

[preston398]

I appreciate the photos.

my issue appears to be a combination of things.
1. Throttle cable has about1/8-1/4 in play so that will get replaced.
2. Throttle cam and cam roller are both worn and have flat spots
3. The main link between the carbs also bends at WOT causing the #1 carb to not open quite as far as the other 3.

For your photo I'm pretty sure you only have it advanced to half throttle. With the throttle cable disconnected I can manually go from idle to WOT with ALL linkages adjusted as per the manual and I have right at 2 inches of travel from idle to WOT. I see no way to only have 1" of travel for full throttle no matter how I adjusted things.

 

[DA250624]

I experienced a similar problem yesterday. I just bought a Sea Ray with a '97 Mariner 115 and have been going through the motor. I discovered the throttle cam was binding up on the the oil feed button when I advanced the throttle. Instead of sliding and pushing the button down, it would stick and start forcing it to the side. A little marine grease underneath the cam seemed to do the trick. I think the oil feed button has been worn down slightly over the years probably from lack of lubrication. You may want to take a look and make sure that's not your culprit.