Merc 3.0 shifting issues

[Jsiples]

Merc 140 hp I4, I previously adjusted the lower shift cable and had fwd,neutral,rev on muffs. Took if out this past weekend. First time trying to shift out of forward to neutral no shift ( stayed in forward ). Then as the day went on after shutting down engine then putting in neutral....it would start in neutral. Even on a few occasions I was able to go through gears while running but was extremely difficult to shift. I had to muscle it to get to neutral from forward. I did notice that the idle was way high at about 1400 so I adjusted that and it helped a bit. I checked the kill switch in the rear and it is functioning. I am just wondering if I need to make another adjustment on the lower shift cable or if on the lower unit the mechanism in there is off. I had the lower unit off over the winter and it looked okay but I am not an expert either. Any advice would be helpful.

 

[tommays]

Re: Merc 3.0 shifting issues

Your idle should be in the 650 RPM range in gear ,high RPM shifts will really beatup the drive

How old is the lower shift cable ? (the one going to the drive ) they bind up and the liner wears with age and can not be adjusted to fix OLD and need to replaced to shift correctly


Tommays

 

[Haut Medoc]

Re: Merc 3.0 shifting issues

Are you talking about the shift interrupter switch?
If so, what tests did you perform to verify that it working correctly?
What you are describing is (to me) a classic case of a bad switch....
Ie, won't come out of gear under load
Is this a new cable?........​

 

[Jsiples]

Re: Merc 3.0 shifting issues

No this is not a new cable. When I had the drive off everything appeared to be operating correctly. As far as the interrupter yes that is what I was referring to. I went back and just pushed it and it killed the engine. Whether it is actually engaging I did not get that far yet, I do know that when in neutral it is directly between each engaging area I guess you could say, which is where it should be. I have a question also when you say rpm at 650 what range should it be in at neutral in water and out. Trying to get a steady idle has been difficult as I am getting a lot of engine shaking anything below 800.

 

[Haut Medoc]

Re: Merc 3.0 shifting issues

650 is in gear, in the water......
800 should be OK on land....
If the switch kills the engine when pushed, it is working....
I think your lower cable is binding...
Why did you feel as though it needed adjustment?
If you were having shifting issues which resulted in you trying to adjust the cable, then it needs to be replaced.....
They go bad, but they don't go out of adjustment.......
A new cable is about $65.....
Now is the time to look at your bellows....
They generally have about the same life span as a shift cable......
Here is a related link.....
http://www.boatfix.com/merc/Servmanl/6/6B4R3.PDF.......
​

 

[Jsiples]

Re: Merc 3.0 shifting issues

Can anyone direct me on where to obtain the shift interrupter switch. I have read that Merc quit selling these? Also, if it IS working how to adjust it if it has somehow gotten out of whack if that is possible?

 

[Jsiples]

Re: Merc 3.0 shifting issues

I had to readjust because I thought I needed to replace it because I lost reverse and neutral last year. Came to find out that the small anchor screws up at the shift plate had vibrated out and core wire was not held by anything. So I re-adjusted the cable for that reason. Prior to going out on the lake I did notice that when on muffs in neutral I could hear a slight clicking sound and the prop was moving in the forward position at a slow but decent rate. MY FAULT, should have done something then.... I am wondering if my adjustment being off might have caused the hard shifting. Like I said when going to neutral from forward it was hard to pull and the throttle lever was basically at ninety degrees before it would try to shift. You all are the experts though if I need to replace I will replace what is needed.

 

[tommays]

Re: Merc 3.0 shifting issues

It will not work well until you do a tuneup and get a good idle speed BUT

http://www.boatfix.com/merc/Servmanl/6/6A2R3.PDF

This is manual 6 which may be the WRONG ONE but on page 2A-18 they go over the adjustment

http://www.boatfix.com/merc/Servmanl/6/6C1R3.PDF

On page 1C-38 they go over checking for excessive play in the shift cable and checking the switch

Tommays

 

[Jsiples]

Re: Merc 3.0 shifting issues

I agree the tune up is a must and will get done here soon waiting on parts to be shipped. Thank you again for the useful links looks like what I am looking for.