Stuffing box behavior

[Tom1340]

I have a 30 mm shaft with conventional stuffing box (adjusted by two nuts on opposite sides of shaft, not by single threaded fitting that the shaft slides thru.). After 6 mos dry storage for hurricane season, I’m cannot get a water drip when underway. I have backed off the adjustment quite a bit without results.
BUT, when I operate in reverse, i do get a good drip. Any ideas on what might be the problem? I have duramax packing, and the stuffing box does not get hot. Thanks, Tom

[Sailmonkey]

Do you have a full keel, or some other sort of deadwood that the shaft passes through directly to the propellor?

Or do you have a strut.

If the deadwood type, it’s possible for there to be a low pressure at the tail end of the cutlass that doesn’t allow water to enter the gland when motoring ahead. Go astern and the prop wash forces water into the gland.

[Tom1340]

It’s a strut. There’s not An air pocket since I get water in reverse. And the configuration is same as it was last spring when all worked well. I’m just now trying to slip the sleeve of the packing 1/4”. See what happens.

[Tom1340]

I backed the compression sleeve well off the packing. I get drips when engine is in neutral or reverse, but when I put transmission in forward, it dries up fast. This is weird. It’s like forward motion of boat is acting as an aspirator, pulling water away from the packing. Except this is a new problem and the shape of the hull/ strut hasn’t changed.