Is it OK to engage prop ?

[Morgan Paul]

Is it OK to engage prop when the boat is out of the water?

I have an old Atomic 4 gas engine with a V-drive. I run the engine out of the water to make sure it will run.

Would it hurt the packing or engine if I was to put the prop in forward and then reverse for say 20 or 30 seconds ?

Paul

[AnchorageGuy]

You won't have any issues with the transmission but your shaft packing gland needs water to lubricate it. I doubt 20 seconds will destroy it but I guess I have to wonder why you want to do this out of the water.

[delmarrey]

Attach a garden hose somewhere it can flow on the cutlass bearing. But don't run it up pass an idle too much and keep people away. The packing (shaft seal) may start to heat up so only run a minute or two at the most.

I do it at the start of each season just to check the trueness of the shaft and vibration. Also, pause long between forward and reverse (spin down).

[ssullivan]

Hmmm... I was always told not to run my engine while in jackstands because the vibration might shift something and knock the boat down.

Figured I'd add this to the thread in case you wanted to believe it...

[Morgan Paul]

Hmmm... I was always told not to run my engine while in jackstands because the vibration might shift something and knock the boat down.

I have no problem running the engine when the boat is on jackstands. My concern was in shifting it out of neutral.

Thanks Chuck, delmarrey and Shean for responding.
If anyone else has an opinion please let me here it.

Thanx,
Paul

[never monday]

don't engage the prop shaft without water on the bearing. It will die quickly.

[Chief Engineer]

Originally Posted by never monday

don't engage the prop shaft without water on the bearing. It will die quickly.

Plus it is dangerous......also the hull is meant to be supported by water....this may cause a binding in the cutlass......20-30 seconds will be the death of the bearing. In case you haven't noticed the price of cutlass bearings has risen remarkably since last year.

As far as checking shaft "trueness" about the only way I know is to take the shaft out.....put it on a "true surface" and roll it or send it to a prop and shaft repair shop.

And as another caution.....if the vessel shifts on the jackstands or the chain that is run between them hangs up on the shaft and your boat goes over, well....you (or your insurance company) might be buying a few more boats

A couple of things you might want to do.

If the engine hasn't been run in so long that you really need to check to see "make sure it will run" you will likely need to repack the shaft. Before running the engine I'd pull the old packing out, that way you can't score the shaft by running it dry.

The trickier part is the possibility of damging the cutlass bearing. The hull can shift shape dramatically when out of the water, so even if (and it's a big "if") the engine was properly aligned the last time it was in the water it will surely be out of line now.

How far out of line will cause damage to the cutlass bearing in a minute of operation? I haven't a clue. Maybe you can get someone else to say it's ok and offer to buy you a new bearing if they are wrong.

Bill