90 hp merc choose gears

[filthy]

hi guys, i have a 96 90 hp merc that now wont give me a gear, i was out fishing and when i was coming back in it just popped out of gear and free revved,no forward no reverse, any ideas on cause would be apreciated, thanks guys

 

[Chris1956]

Are you sure it was the gears or did the prop hub fail? Take a look under the cowling and see if the shift linkage moves when you move the throttle lever.

 

[racerone]

It is unlikely that it " popped " out of gear.--------Drain the gear oil in the lower unit and post what you find.

 

[Texasmark]

Did you hit something? Had you recently hit something where you spun the hub and had to recycle power to get it to reseat? If you spun the prop hub you can put the engine in gear, power off and grasp a prop blade and attempt to turn it. If you can, look at the prop nut while you do. does it turn too or is it stationary. If stationary you need a new prop or repair of that one.

If it turns too, then Racerone is onto it. However, if you blew the lower unit, then the clutch dog pin (through the prop shaft) shearing is the first thing that comes to mind since nothing works one would think you would have heard some kind of noise or some kind of indication that something had gone wrong.

Mark

 

[Chris1956]

Mark, The clutch dog pin attaches it to the plunger that moves the clutch dog. The clutch dog is splined to the prop shaft, and the two gears ride on bushings. It is unlikely the clutch pin will break, as the shift linkage would be the only way they would happen, and it is not the weakest part by far.

 

[filthy]

Thanks guys, at least that gives me a few things to check, its a stainless prop so its not a spun hub, I did hit something a fair while back but havnt had any trouble till now, Was in open water and when I throttled up it just threw itself out of gear, but yeah looks like lower unit is coming off, will drain the oil and see whats in it first tho

 

[Texasmark]

Thanks guys, at least that gives me a few things to check, its a stainless prop so its not a spun hub, I did hit something a fair while back but havnt had any trouble till now, Was in open water and when I throttled up it just threw itself out of gear, but yeah looks like lower unit is coming off, will drain the oil and see whats in it first tho

Stainless use rubber hubs too; and plastic. Don't use SS as a criteria for a slipping hub.

Mark

 

[Texasmark]

Mark, The clutch dog pin attaches it to the plunger that moves the clutch dog. The clutch dog is splined to the prop shaft, and the two gears ride on bushings. It is unlikely the clutch pin will break, as the shift linkage would be the only way they would happen, and it is not the weakest part by far.

I know how it works. I have described it's operation on here many times. I don't see the shifting linkage as being a problem as he said he was running along in gear meaning to me that the linkage wasn't being used.

Mark

 

[filthy]

Thanks guys, Err yup spun prop hub, cheap fix

 

[Faztbullet]

The pin thru clutch dog has very little load on it anytime so it cannot shear, its only purpose is to slide clutch dog in/out of gear.