Gearbox misalignment problem???

[MystyBlue2]

Hi folks i have a mariner 25hp 2 stroke 1986 (jap model)

I changed waterpump in may and everything seemed fine but today i found it has started to grind in reverse, closer inspection if i select reverse it seems as though the gears are parallel to eachother and wont engage and cause a horrible grinding noise, the shift rod will not drop down it seems to only flex and will only slot into gear if i rotate the prop 1" clockwise or anti clockwise, obviously i cannot do this when i am running out at sea, I have removed the cables to see if the cable is at fault and same issue using my hand on the shift lever so i think i can rule that out. Does this seem like a misalignment issue or maybe gearbox on its way out.

When i droped lower unit to change water pump i made sure it was in reverse before i removed the unit. Neutral and forward gear selects just fine its only on reverse this is happening. I also droped lower unit oil today and i had small metal shavings in oil, (not huge chunks and not alot) but enough to make me want to get this grinding sorted before it turns out to be a disaster.

Hope ive put enough info in and hope it makes sence,

Penny for your thoughts people, cheers

 

[BruceK]

shiftshaft, cam, sliding clutch or retaining pin problem. Only way to find out for sure is to strip it down

 

[MystyBlue2]

I was afraid of that!! Seems strange it engages neutral and forward perfectly with no noise at all, when running in forward at WOT it dosnt wine or anything only reverse has issues selecting. It will eventually engage after i try reverse, then forward a bit then it will engage but will grind and crunch if gears are not lining up with eachother. Cheers for your comment ?

 

[MystyBlue2]

Could it be possible that if i have altered the shift rod setting slightly when removing the lower unit and havnt put it back in the exact place? It only started this after i removed the unit

 

[BruceK]

Yes it could be. And if the issue was immediately after doing the water pump highly likely. But it's pointless guessing. You need to start disassembly and inspection. Good news is parts are available if it's any of the above and surprisingly cheap.

 

[spannerman]

Drop the gearbox and make sure the shift lever is in neutral and the gearbox is in neutral by rotating prop shaft, then refit gearbox. Check the shift function before fitting all the bolts. The gear shift is spring loaded towards forward so check the splined shaft doesn’t rotate before you refit the gearbox.

 

[MystyBlue2]

Awesome guys thanks for your help im off work tomorrow so i will fill in my time off by removing and refit lol cheers folks ?