Hard to shift into neutral

[BlaineC]

I have a 2003 Mercury 115 EFI outboard (s/n OT577928) that I have a hard time shifting into neutral. Sometimes it will go right in smoothly and other times I have to use 2 hands and really pull on it to get it into neutral. The engine starts and runs good and has no issues shifting into forward or reverse. I have replaced the shift cable that runs from the controls up by the the steering back to the motor and that did not solve my problem. Today I pulled the shift/neutral switch out and tested it on a meter....no continuity when the plunger is extended and continuity when it is depressed. It seems to be in adjustment as the plunger to the switch was between the marks on the slider that is connected to the shift mechanism. Before I pulled the switch out I started the outboard and depressed the plunger on the shift/neutral switch by hand but I did not hear any change in RPMs. That was with the motor in neutral. I didn't think to try it with the engine in gear. I am new to boats and learning as I go. I have a Mercury Service Manual for this engine but I cant find much info on this switch or where else to look to find a solution. My next step is to pull the control handle apart and see if there is a mechanical issue there that could be causing this. When I bought the boat/engine the engine was in pieces. The pistons and all the internals were together but i had to put the cams in and all the bolt on parts. A fuel pump was all I replaced to get it running. The boat is usable as is but it makes it pretty stressful coming into the dock. Any help or thoughts on what to check would be greatly appreciated. Thanks.

 

[Chris1956]

What is your idle RPM? Too high and it makes it hard to get out of gear. You need to see if the shift cut-out switch really kills part of the motor, to make shifting easier.

Also, as you pull back on the gearshift, with the engine running in gear in the water, the cut-out switch should be activated by the linkage deflection.

 

[BlaineC]

Thanks for the reply Chris.
I was reading that about the RPMs but being that it is a fuel Injected engine I don’t think there is an adjustment for idle RPM. I dont know what the rpms are at idle off the top of my head. I’ll have to check. I’ll look into the switch more but when I tested it it seems fine. However it doesn’t seem to do anything to the engine when I manually depress the switch. I hate to just throw money at it but I may just replace it and go from there. I also need to look at the adjustment... my understanding of how a shift switch works was not what I learned from reading up on it. And I think I was confusing it with a neutral safety switch too.

Is it correct that once the engine is in neutral that the switch should no longer be depressed allowing the motor to run as it should or is the the motor “interrupted” whenever it is in neutral?

The boat is at a storage lot. Hopefully I’ll get over there again tomorrow to troubleshoot some more.

 

[BlaineC]

So it looks like my RPMs may be way too high. Just running out of the water with no load they are around 1300. That is assuming my tach is correct. So how do you lower RPMs on an electronic fuel injected engine?....guess I have some more reading to do to figure that one out.

Also on a hunch I tested to make sure my shift switch was actually going to ground on the engine and it does have continuity between the switch and engine. So the switch seems to be working but what I don't understand is with the engine running and I depress that switch, shouldn't i see or hear some change in the engine?

 

[BlaineC]

I have had the boat out several times and I still have the same issue of not being able shift into neutral from forward or reverse easily. If I turn the engine off it will go right in just like it does running on the hose. My RPMs are around 1100 which is high. I replaced the IAC valve with no change in RPMs. I checked my hoses for cracks and could not see any obvious leaks so to double check for vacuum leaks I sprayed all my hose connections, the seams where intake mounts and any other area that I thought could cause a vacuum leak with starting fluid with the engine running with no change in engine sound or RPMs. I plugged in a test light and it gave me the code for everything is operating as it should. Any suggestions or ideas of what to look at next?

 

[Chris1956]

Can you simply adjust the throttle cable to push the throttle closed more, retarding the timing? On Mercury carb motors, the carbs are closed and the throttle cable pushes the throttle arm to retard the timing, thereby controlling the idle RPM.

 

[BlaineC]

I don't believe so. This is a fuel injected engine and I think when I looked at the linkage it was as far closed as possible but I will double check. I'm going over to pull the thermosensor to test that...I read somewhere that if that sensor is bad it could cause the engine to constantly run as if it is in warm up mode.

 

[BlaineC]

Thermosensor tested fine. I was able to turn the adjustment on the throttle cable a few turns...not sure it actually pushed it any further closed but we will find out if it changed anything the next time I can get the boat out....hopefully tomorrow.

 

[stikboyy]

It sounds to me like your throttle plates aren't synchronized and are potentially being held open to far esentially causing a vacuum "leak". The plates need to be synchronized using a set of vacumate or similar tool. There is a detailed procedure in the service manual for your motor (Service manual 881980R02). Once you have the throttle plates synchronized and set up to achieve your idle rpm you must also confirm the throttle position sensor is set up correctly.

 

[BlaineC]

I"ll look into that but what I found the other day was a screw on the intake that was hidden by the silencer. It appeared to be a limit screw for the intake valve/plate (not sure what they would be called). I turned it 3/8 turn and brought my idle down to close where it needs to be. It shifts much better now. Still a little stiff going into neutral from forward but reverse into neutral is perfect. Ill try a little fine tuning next time I'm on the water and hopefully that is all it is. . I'm a little surprised this adjustment wasn't mentioned in the troubleshooting section...or maybe I just missed it. Thanks for the suggestions

 

[jimmbo]

Is the throttle cable length correctly adjusted, The Cable length needs to be adjusted to keep a bit of preload(pressure against the idle stop) any time the idle speed is adjusted. Also it would need to be set if the Cable itself was replaced. Too little or no preload, the Idle speed may not be consistent, too much, and the engine may be hard to shift into Neutral,

 

[BlaineC]

I think the cable is adjusted as it shows in the manual. I had the boat out yesterday and it shifted great. The idle stayed right where it should be. Hopefully it is all dialed in now. I'll look up the throttle cable adjustment again just to be sure...thanks for the suggestion.