Drivetrain coupling shaft problem ?

[Delawaredave]

1982 Hunter 27. Yanmar 1GM. Newbie. All seemingly stock.

The pin fell out on the shaft coupling after the gearbox (at least I think that's the gearbox behind the engine). Took coupling apart and put pin back in.

However, on the coupling are two "set screws" (see pic below) that are not bottoming out on the shaft. And when I look at the shaft, there's a visible "divot" (see pic) that looks like the set screws should bottom out into.

But looking at the wear marks on the shaft, it looks like it always has been this way.

The shaft does slide fore/aft - I'm surprised - the shaft can't "slide out the back of the boat", can it ? Does not seem like I can slide it forward so that the "divot" is under the set screw.

I went under the boat - the prop ends about 1.5" before the rudder (I should have measured it more accurately) - is that the normal location ?

Thanks !!!

 

[Ken13559]

Prop 1.5" from rudder? That seems pretty close. Too close. One thing you can do is dismantle the shaft coupling and have a better look.

 

[Claude L.-Auger]

Looking at the picture we see a mark about 1 & 1/2 inch from the coupling. Methinks the shaft should go in to that mark, which would give you about 3" before the rudder, a better distance than the 1 & 1/2 you reported. Sliding the shaft in to the mark would also bring the set screws in line with the divots. They should not be bottoming out but should indeed be tight on the shaft. When they bottom out they fill no purpose. I would remove the set screws completely and try to bring the shaft up on the coupling. It might be easier to dissassemble the coupling and push it back on the shaft, having blocked the prop from going further on the rudder. Do not bang on coupling or prop as you might create damage to the gearbox (yes it is the gearbox behind the engine). Good luck

 

[Delawaredave]

Thanks ! I'll go down and see if I can get shaft to slide forward.

 

[Saillife]

Can't help with the connection at the stuffing box.

As to where the screw should be under your boat, the screw should be no more than the diameter of the shaft away from your cutlass bearing. If your shaft is an inch in diameter than it should be an inch from the bearing. The other issue to check on the screw is clearance between it and your hull.

Brian

 

[Delawaredave]

OK. I removed set screws, moved shaft forward so the "set screws" contact the shaft inside the coupling. Believe correct.

Question: There's a small drip (1 drop every 2-3 seconds) coming from the back of the brass "cap" that the shaft goes through (see below).

Is this normal ? Too much ? Should I tighten the brass nut a little ? Don't want to make worse. Thanks !!!

 

[Ken13559]

I believe the guide is couple drips per minute when shaft is spinning. So with stationary shaft, you get drips in seconds, that's too much.

 

[Claude L.-Auger]

Your best bet would be to read Maine Sail's article on packing gland adjustment. Here is an excerp from it but do go to the full article:

" Here's the point. All traditional stuffing boxes, including ones packed with Gore GFO, must drip slightly when the shaft is spinning. If water does not drip you WILL ruin the shaft. Gore GFO can drip as little as 1 drop per two minutes and still run cool to the touch but traditional flaxes need to drip more like 3 to 10 drops per minute when the shaft is spinning. The closer you get to three drops per minute, with standard flax, the more shaft wear you will get. Never adjust the stuffing box with a wrench unless you have to! Always hand adjust then lock the nuts agaist each other with wrenches. If you over tighten you run the risk of ruining the packing as it does not have much rebound and does seem to have a memory.

So in short break the large nut from the lock nut with wrenches then adjust by hand a 1/4 turn at a time until you get the minimal drips and still have a cool to the touch stuffing box. Traditional flax boxes should run cool to the touch not warm. GFO can run slightly warm unless you are in a high silt area then more cooling water is necessary. Some folks claim derip free operation with GFO"