Loud knocking with black smoke - Yanmar 70
So, yesterday we are 10 minutes into our weekend get-away when all of a sudden I hear a loud knocking below and dark black smoke starts billowing from the exhaust.
Ive got very little power and the motor is vibrating.
So I put it in neutral and shut it down to ponder my options. We are now in a river that is running 4 knots with the spring freshet so I need to do something
quickly. I decide to turn around and see if the motor will make progress up river and hopefully last back to the Marina. If not we will have to drop the hook and wait for a tow.
So I start the engine and try to put it in gear but it won't go into forward. Whatever has let go seems to involve the tranny as well. After trying a few times It goes into reverse and then I quickly jam it in to forward.
We're now are making 1 knot against the river back to our slip with black smoke pouring out the back and the boat feeling like it's going to shake apart while I contemplate a $15,000 re-power - bad start to the day.
An hour later we are back at the marina, whew!
Anybody want to hazard a guess?