Outboard engine gearboxes

[C08]

My outboard has developed an occasional fault. It locks in gear and the remote control will not go into neutral. Turning off the engine frees it up an I can do neutral and restart ok. I do not think it is the remotes or cages. The engine is a 25 hp Yamaha. I suspect the gear that slides on the splined shaft is sticking, a burr or something. I have changed the gear oil and no sign of any metal swarf or water in oil. It could of course be the selector for that pushes the gear back or forward to change the gear FWD to neutral etc. I have only once had one of these apart which looks inevitable to me but I would appreciate any alternative views on this problem. Engine is 6 years but only around 400 hrs.

 

[penfold]

If you remove the cable at the engine end can it be shifted by hand with the engine running?

 

[C08]

If you remove the cable at the engine end can it be shifted by hand with the engine running?

Because this is an intermittent fault this is unlikely to show anything useful but thanks as I am really puzzled.

 

[ChromeDome]

Check/clean/wonderspray* all moving parts involved, shafts and grommets and see if that helps

*preferably something that lubes more than WD40

 

[Rolling Stone]

Disconect the cable from the engine shift lever and make sure the control is free and the cable/control box isn't stiff - the cables wear out and the boxes need greasing.
Make sure the engine's gear lever aligns with the cable end in neutral - there's a threaded section to align it up or down.
Ensure everything is greased.
Gearboxes rarely give trouble, it's the remote bits that wear out.

 

[QBhoy]

Good advice above. 2 things from me additionally perhaps.
Has the gearbox been off previously, perhaps resulting in the gear linkage mechanism rod/fitting, being slightly off ?
But perhaps a more common reason for the very issue you have, is if the idle rpm speed of the engine is too high. This being the case, it’s mechanically near impossible for the thing to come out of gear as it should. Larger and more modern engines feature a shift switch that actually cuts the ignition to couple of cylinders or more, reducing the idle rpm by about half, for a split second, just to make it easier or even possible to come out of gear and into neutral. Is this perhaps the case for you ?

 

[C08]

Good advice above. 2 things from me additionally perhaps.
Has the gearbox been off previously, perhaps resulting in the gear linkage mechanism rod/fitting, being slightly off ?
But perhaps a more common reason for the very issue you have, is if the idle rpm speed of the engine is too high. This being the case, it’s mechanically near impossible for the thing to come out of gear as it should. Larger and more modern engines feature a shift switch that actually cuts the ignition to couple of cylinders or more, reducing the idle rpm by about half, for a split second, just to make it easier or even possible to come out of gear and into neutral. Is this perhaps the case for you ?

Thank you so much that is interesting, I did not know about idle speed affecting coming out of gear although switching off the engine is effectively reducing the tickover to zero. It idles at 900 rpm around the manufacturer's spec but perhaps the remote control or cable for the throttle is sticking i.e. not shutting off properly on occassion and that is causing it jamming in gear. So I have been looking at the gear side of things and it may well be the problem is with the throttle remote control or the throttle cable itself. If this is the case a much easier fix than the gearbox!