alpha one not shifting??

Morning All. While underway my engine started to bog for a couple seconds than shot up to 6000! Didnt hit anything and prop wasn't spun. Placed shifter in fwd/rev with engine off and prop locked, like it should, in both gears. started engine and when placed in fwd/rev, just reved up felt briefly like gears were trying to lock then nothing. thoughts?

Re: alpha one not shifting??

not much that can go wrong.

spun prop hub
coupler
gear teeth broke off
broke drive shaft(s)

time for some investigation.

-drain the lub and see if ya got metal fragments
-look at the back of the engine and look for rubber dust
-pull drive and look to see if the coupler has any female splines left
-pull the top cap of the drive and ya can see a couple of the gears to see if any teeth are left
-separate the drive upper from lower. see if the drive shafts are still one piece.

others will probably have more for ya as i'm only a shade tree mech...
best i can come up with off the top of my head

oh, did it overheat? if coupler, best i understand. if the rubber goes it will still cool if kept at a low rpm. if the splines go it'll overheat as nothing is spinning pass that point. like the impeller...

Re: alpha one not shifting??

a little info on your boat, perhaps? engine, drive, gear ratio etc...

i had the same thing happen to me with my alpha 1...and i shredded the top unit gears. lower unit will still shift, but the power will not be transferred to the lower unit at all. what did your engine temps look like? if they spiked, the impeller is not pulling any cooling water, and chances are good you may have a similar problem. pull the top cover off the upper unit and take a peek at those gears.

if they are ok, you may have a spun coupler, which sucks a lot. i am not sure how to check for that, maybe some of the more experienced people on here can help?

anyway, if it is the drive, i ended up grabbing an SE-106 from sterndrive engineering, direct replacement for the alpha 1, and it comes with a sweet 3 year warranty.