Mercruiser 260.. stuck in gear ar after impeller change, and dies when using shifter.

I just got done replacing the impeller on my 1979 merc 260. It was a bit differnt inside than the youtube video I watched. The shifter was spline, not a hook like design I watched.

The replacement went smooth. The old impeller looked brand new, which considering I have no history on the PO and care...made me feel better about the maintnence of this boat prior to sitting for so long.

We got the drive shaft up, and the gear shifter seemed to line up. We tightened everything up and cranked her up. within a few revs, water was gushing out the exhaust...but we noticed the prop shaft was also spinning(no prop on boat).

It cranks like this in neutral, and if you do throttle only the boat revs. If you push foward to go into gear the boat dies. Fast or slow. Same thing for reverse.

It was not doing this prior to the impeller change? Any ideas? did we get the shifter gear in wrong or off? It was removed in forward, and installed in 'forward'.

You can turn the prop by hand one direction, but not the other. And you can hear gears working when you do it the diection your allowed.

Re: Mercruiser 260.. stuck in gear ar after impeller change, and dies when using shif

you have to make sure the lower half of the drive is in forward gear and the shift shoe in the upper is facing straight forward upon reassembly

its quite possible the splines are off one or two and when you shift into forward the cable is binding and activating the shift interrupt switch

Re: Mercruiser 260.. stuck in gear ar after impeller change, and dies when using shif

Is it possibly to align this without dropping the out drive again? Not a difficult task, just filled the unit with oil, though.

So those two L shapped piecs you can see from under/back of the drive is for shifting?

Just to confirm.. if I have the out drive off.. I can turn the spline by hand, and in neutral i'll be able ot spin the prop both ways freely. In forward one way will rachet, other way won't turn. And reverse is opposite of forward?

Re: Mercruiser 260.. stuck in gear ar after impeller change, and dies when using shif

put the control box in full fwd, turn splined shaft fully clockwise, prop shaft should lock counterclockwise. raise lower unit , catch the front stud with a nut to hold the unit in place, align lower shift shaft with splined shaft making sure the lower shoe is in a straight line, start 2 side nuts MAKING SURE THE 2 SHOES STAY LINED UP, tighten nuts .installl remaining nuts/bolts.

Re: Mercruiser 260.. stuck in gear ar after impeller change, and dies when using shif

Got it fixed shortly after this post.. Looking from the back of the out drive I saw the pieces that needed to line up. Dropped the out drive enough, lined that up and tightened it all down..then filled oil.


Everything is working as expected now runs, idles, shifts.. finishing up fluids today, and planning to take the boat out next weekend.