Is my lower unit bad???

[menaghtroy]

I have a 1999 mercury 225 DFI v6 3.0. The other day I put the boat in gear and was at about 2000 rpm when the motor made acrazy noise and all of a sudden lost all power. The engine will run fine and rev up but the prop will not spin. I removed the lower unit and the main shaft and prop shaft seem to look fine however i cant see the lower gears does anyone know a way to trouble shoot this?

 

[mr 88]

Re: Is my lower unit bad???

Maybe you spun the prop hub? Not a great description "crazy noise".

 

[Faztbullet]

Re: Is my lower unit bad???

Check your gear oil, if full of metal debris and the pinion or driveshaft has failed. The single bearing driveshaft was bad about this if you had a hotfoot.

 

[bobkyle2]

Re: Is my lower unit bad???

Try a spare prop.

 

[ufm82]

Re: Is my lower unit bad???

If you can eliminate non-engine issues (shifter cable, linkage, etc) and you have the L/U off, can you shift it into gear? If you can get it into gear is it smooth when you turn the driveshaft? To visibly inspect the carrier you'll need to pull the prop and get the tool to remove the big carrier nut that screws into the foot. (It's as big as the inside of the bullet- there is a spanner wrench to remove it.) Easiest way to check is as recommended- pull the drain plug and look for remnants. This is assuming the plastic spline insert isn't destroyed.