Yanmar 2GM difficulty going into gear

[webcraft]

.
The Yanmar 2GM in Avy-J is recovering well from a ten year rest, but is reluctant to go into gear before revving up.

Have adjusted the throttle cable as far as possible to give maybe three quarters of an inch movement before it throttles up, so the gear lever moves that far before the revs increase - but it still does not engage immediately. Reverse is mostly OK, but the only way to get it to engage in ahead reliably is to very quickly move it agressively forward to maybe half throttle then when it engages pull it back to idle.

Engine oil is clean and just above the mark on the gearbox dipstick.


- W

 

[coopec]

There's a fair few thread that are relevant

https://forums.sailboatowners.com/threads/yanmar-transmission.127118/

https://forums.sailboatowners.com/threads/no-forward-or-reverse.145212/

https://forums.sailboatowners.com/threads/forward-reverse-neutral.9498/

https://forums.sailboatowners.com/threads/shift-throttle-cables.145721/


Yanmar 2gmf stuck in reverse gear - SailNet Community
https://www.sailnet.com › forums › diesel › 104243-yanmar-2gmf-stuck-r...

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[VicS]

.
The Yanmar 2GM in Avy-J is recovering well from a ten year rest, but is reluctant to go into gear before revving up.

Have adjusted the throttle cable as far as possible to give maybe three quarters of an inch movement before it throttles up, so the gear lever moves that far before the revs increase - but it still does not engage immediately. Reverse is mostly OK, but the only way to get it to engage in ahead reliably is to very quickly move it agressively forward to maybe half throttle then when it engages pull it back to idle.

Engine oil is clean and just above the mark on the gearbox dipstick.


- W

Clutch cones worn most likely . A common problem

 

[Kelpie]

How does it behave if you disconnect the cables and operate the gear shift and throttle manually?

 

[webcraft]

How does it behave if you disconnect the cables and operate the gear shift and throttle manually?

Dunno, but I suspect it would behave perfectly. The issue seems to be that the engine begins to rev before the gear lever is moved all the way.

- W

 

[Kelpie]

Dunno, but I suspect it would behave perfectly. The issue seems to be that the engine begins to rev before the gear lever is moved all the way.

- W

If your engine access is ok then I'd definitely try this first. Hopefully it is just an issue with the controls and you won't have to start stripping the gearbox.

 

[VicS]

If your engine access is ok then I'd definitely try this first. Hopefully it is just an issue with the controls and you won't have to start stripping the gearbox.

+ 1

When connecting the cable to the shift lever on the gear box be sure that the lever is truly in the neutral position when the remote control lever is in the neutral position.
If alter things to try to force the box into gear you will probably create more problems than you will solve

 

[webcraft]

+ 1

When connecting the cable to the shift lever on the gear box be sure that the lever is truly in the neutral position when the remote control lever is in the neutral position.
If alter things to try to force the box into gear you will probably create more problems than you will solve

It seems to go into astern better than ahead, so it is possible the gear lever is not in dead centre neutral when the morse lever is.

There is no slack in the gear cable - the lever on the box starts to move the second you start to move the morse lever. Could there be too much slack/length in the cable, causing some of the movement to be taken up by the whole cable being displaced?


- W

 

[VicS]

It seems to go into astern better than ahead, so it is possible the gear lever is not in dead centre neutral when the morse lever is.

There is no slack in the gear cable - the lever on the box starts to move the second you start to move the morse lever. Could there be too much slack/length in the cable, causing some of the movement to be taken up by the whole cable being displaced?


- W

The point I am trying to make is that the shift lever on the gearbox must be in precisely the neutral position when the morse lever is in its neutral position.
Some gearboxes have a detent ball and spring that positively locates the shift lever in the neutral position but IIRC others do not so have to be positioned according to the workshop manual instructions
when connecting/ adjusting the cable
You should find this explained in the manual.