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Shaft Nut Water Leak


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ok i could use some advice here. I have a 2006 vlx 340 monsoon.

Recently moored the boat and went back yesturday and noticed that there is a steady drip coming from between the 2 nuts on the shaft. Its about 1-2 drips per second with boat turned off and seemed about the same when turned on boat in idle. So i brought the boat home today to fix this and do some other work to it.

I am assuming i have a water cooled shaft so i ran the boat with a "fake a lake" and checked for leak and there was no drips at all when idle.

From the seaching i have done here it seems i need a 2 x 1 7/8" wrench to adjust these till it stops leaking when boat off and drips every 5-30 secs when on.

Is putting the boat back in the water and tightening the nut untill the drip stops while boat turned off then check to make sure there are some drips while on the best solution?

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I am assuming i have a water cooled shaft so i ran the boat with a "fake a lake" and checked for leak and there was no drips at all when idle.

Is putting the boat back in the water and tightening the nut untill the drip stops while boat turned off then check to make sure there are some drips while on the best solution?

I believe fake-a-lake for engine running/cooling purposes?...so water isn't getting to the propshaft. On the water is where you need to do it if you want to see immediately results. You could tighten the nuts 1/4 turn with the boat on the trailer...then see the results when you go back out. Retighten as necessary.

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Thanks for the replies.

I have tried a number of times now to tighten the nut but cant seem to get any movement. Should i be holding the back "thin" nut while i tighten the front "large" nut clockwise?

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Thanks for the replies.

I have tried a number of times now to tighten the nut but cant seem to get any movement. Should i be holding the back "thin" nut while i tighten the front "large" nut clockwise?

Loosen the jam nut (in back) before tightening the packing nut. Once you have tightened the packing nut, tighten down the jam nut to hold it in place. Make very small adjustments on the packing nut (no more than a quarter turn at a time) as it doesn't take much to adjust it. After each adjustment, run the boat some and check the drip rate. Make sure the stuffing box doesn't get hot to the touch. This is an indication you have the packing too tight. It is a trial and error process that can take a few tries but isn't very hard.

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It's time for a tech article on how to tighten the stupid packing nut!

Guess I just volunteered huh?

You're perfect for the job.

Crazy.gif

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It's time for a tech article on how to tighten the stupid packing nut!

Guess I just volunteered huh?

You're perfect for the job.

Crazy.gif

Wow Jack, you put on the witty pants today huh?

Took you awhile to clear your head after all that teak oil and napatha you were huffing over the winter?

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My boat has been "leaking" for a while now. So, thanks to the Crew I looked at the Packing nut a couple of days ago and I had a drip rate of 1 every second or two. I made the corrections just like BlastRlxi said. Hopefully, my "leak" is fixed.

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Finally got it done using a couple of cheap adjustable plumbing wrenchs. Not a easy task on a v drive. thanks again.. Cheers.gif

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  • 2 weeks later...
Thanks for the replies.

I have tried a number of times now to tighten the nut but cant seem to get any movement. Should i be holding the back "thin" nut while i tighten the front "large" nut clockwise?

Loosen the jam nut (in back) before tightening the packing nut. Once you have tightened the packing nut, tighten down the jam nut to hold it in place. Make very small adjustments on the packing nut (no more than a quarter turn at a time) as it doesn't take much to adjust it. After each adjustment, run the boat some and check the drip rate. Make sure the stuffing box doesn't get hot to the touch. This is an indication you have the packing too tight. It is a trial and error process that can take a few tries but isn't very hard.

What's the stuffing box? Sorry, I don't know enough about engines, but I'm getting this same problem and I would hate to take it to the dealer just for this.

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To get this task done right, your boat has to be in the water for about 24 hrs prior to and during the adjustment. After a day of boating will work, but I would keep rechecking. You have to give the packing time to saturate and expand. If you trailer your boat, constant readjustment may be nessessary, because your packing will never have time to properly expand with a complete saturation. Here is where a run dry (dripless) type packing comes in handy. Others might be able to ellaberate on this, as I am not familar with the dripless packings.

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To get this task done right, your boat has to be in the water for about 24 hrs prior to and during the adjustment. After a day of boating will work, but I would keep rechecking. You have to give the packing time to saturate and expand. If you trailer your boat, constant readjustment may be nessessary, because your packing will never have time to properly expand with a complete saturation. Here is where a run dry (dripless) type packing comes in handy. Others might be able to ellaberate on this, as I am not familar with the dripless packings.

Thanks, I'll give it a try. Could there be any other cause of the leak?

This is what's happening: the water is slowly shooting up the propeller shaft from the seam between the shaft and the nut. So it's shooting up toward the transmission and it's pretty steady, more than a drip. I just don't want to go buy a wrench and spend the time cutting it down if it's likely something else.

Also, is the packing that black polymer piece wrapped around the shaft and held together with several hose clamps (silver clamp with the screw to tighten)?

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The packing is a flax rope saturated with wax wrapped around the shaft just inside the nut where the water is squirting on your boat. The packing 'box' is the nut and the brass fixture it's screwed onto.

The adjustment above will fix your problem. Basically - tightening the nut will compress the packing between the nut and the edge of the mount it's screwed onto compressing it to seal the leak.

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Thanks for the replies.

I have tried a number of times now to tighten the nut but cant seem to get any movement. Should i be holding the back "thin" nut while i tighten the front "large" nut clockwise?

Loosen the jam nut (in back) before tightening the packing nut. Once you have tightened the packing nut, tighten down the jam nut to hold it in place. Make very small adjustments on the packing nut (no more than a quarter turn at a time) as it doesn't take much to adjust it. After each adjustment, run the boat some and check the drip rate. Make sure the stuffing box doesn't get hot to the touch. This is an indication you have the packing too tight. It is a trial and error process that can take a few tries but isn't very hard.

It can be pretty difficult to set the packing nut at the perfect spot. Loosen the thin back up nut. I then tighten the big nut until it doesn't drip at all when just sitting in the water, I just use my hand, then I lock it down with the little nut with a wrench. Always worked fine for me. The difference between too much drip and no drip can be as little as one tenth of a turn. Its not like you are trying to hold back a bunch of pressure. Tighening by hand also prevents me from compressing the packing and heating everything up. I have worked on large industrial pumps with this set up fo over 20 years and boat packings can be the trickiest to set since you have so little pressure to push the water through.

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Thanks for the replies.

I have tried a number of times now to tighten the nut but cant seem to get any movement. Should i be holding the back "thin" nut while i tighten the front "large" nut clockwise?

Loosen the jam nut (in back) before tightening the packing nut. Once you have tightened the packing nut, tighten down the jam nut to hold it in place. Make very small adjustments on the packing nut (no more than a quarter turn at a time) as it doesn't take much to adjust it. After each adjustment, run the boat some and check the drip rate. Make sure the stuffing box doesn't get hot to the touch. This is an indication you have the packing too tight. It is a trial and error process that can take a few tries but isn't very hard.

It can be pretty difficult to set the packing nut at the perfect spot. Loosen the thin back up nut. I then tighten the big nut until it doesn't drip at all when just sitting in the water, I just use my hand, then I lock it down with the little nut with a wrench. Always worked fine for me. The difference between too much drip and no drip can be as little as one tenth of a turn. Its not like you are trying to hold back a bunch of pressure. Tighening by hand also prevents me from compressing the packing and heating everything up. I have worked on large industrial pumps with this set up fo over 20 years and boat packings can be the trickiest to set since you have so little pressure to push the water through.

Just so you know, marinas that deal with big boat inboards tighten prop shafts all the time. I took mine to one and they basically tightened my prop shaft for free with the winterization and oil change. It took them about 5 minutes. They had special wrenches and didn't have to remove the floor board. Of course, they messed up the winterization and oil change.....

They'd probably tighten yours for less than the cost of a Chinese Wrench. (And I'm guessing this doesn't need to be done often.) After reading the other posts I'm a bit concerned... but I haven't had any problems.

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is it easier with two of these wrenches or is one enough? Mine is leaking pretty good right now and want to get it fixed.

You will need two wrenches. One will hold the adjusting nut steady while you use the other wrench to tighten the jam nut. If you try to tighten the jam nut without holding the adjustment nut steady, you will turn both at the same time and, as skinut pointed out, if the adjustment nut moves just a little, it will cause the packing to be overtightened.

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