Gears wont engage while under water

[The Water Boy]

My '78 OMC Stern drive is having problems engaging gears, both forward and reverse while the motor is in the water. When I take the boat out of the water, the drive will engage perfectly, but as soon as it's back in the water, no go. It sounds like it's trying to engage, but like it just won't slip into place.
If I take the prop off and then put it into the water, it will engage perfectly, but as soon as I put the prop back on and put the boat back into the water, it won't engage again.
If I pull out of the water, put it into to gear and then back down into the water again, it will stay in gear, but as soon as I shift back into neutral while I'm in the water, it won't shift into drive again (forward or reverse). As long as it's into the water above the lower gear casing, it wont engage.
Someone suggested getting a new prop, but that didn't help. I've also had a suggestion to replace the thrust washer, but I haven't tried that yet.
Can anyone help?

 

[Mystic Dragon]

Re: Gears wont engage while under water

Water Boy,

Check some of the other posts. This looks like it may be related to the ESA Module, idle speed and the shift interuptor switch.

 

[fendersfender]

Re: Gears wont engage while under water

i'm going to say that it is the lower unit itself...worn-out clutch dogs......with prop in water there is too much pressure on those worn out parts to engage gears....i would say that its time for a rebuild

 

[fendersfender]

Re: Gears wont engage while under water

also...the worst thing to do with these drives is to have the idle set too high...idle should be about 650 rpm......a high idle will cause premature failure of clutch dogs and will result in a problem like yours.

 

[Bondo]

Re: Gears wont engage while under water

1978,........OMC.............

Is that 1 of those Electric Shift outdrives that Never shift right,..??..??.........