Can any one tell me what would cause my stuffing box and prop shaft to be hot to the touch? It is dripping at the reccommended rate and is hotter than I think it should be. It is a brand new shaft and stuffing box. Oday 28 Any solutions would be great. Thanks Tom
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Hot Stuff...
Loosen the Stuffing Box Nut a bit more and allow it to drip more than the recomended amount.More important to not over heat it than to keep it dripping at a certain rate..that "recomended" amount is just a basic guideline..it's not carved in stone..and for sure it should drip more when the motor is running and the trans is in gear. Next question is:are you sure you used the correct size flax when you restuffed the box? Could a P/Owner have used oversized flax because of wear on the shaft and you came in with new Prop Shaft and the same size flax? Measure the inside of you Stuffing Box Nut,then subtract the Shaft diameter from that..the number you come up with is then divided by two..that should be close to the size flax you need.Good Luck and Fair Winds>>> David
Loosen the Stuffing Box Nut a bit more and allow it to drip more than the recomended amount.More important to not over heat it than to keep it dripping at a certain rate..that "recomended" amount is just a basic guideline..it's not carved in stone..and for sure it should drip more when the motor is running and the trans is in gear. Next question is:are you sure you used the correct size flax when you restuffed the box? Could a P/Owner have used oversized flax because of wear on the shaft and you came in with new Prop Shaft and the same size flax? Measure the inside of you Stuffing Box Nut,then subtract the Shaft diameter from that..the number you come up with is then divided by two..that should be close to the size flax you need.Good Luck and Fair Winds>>> David
Did you paint It?
Sometimes , a painted shaft will cause it. If you painted up to the thru hull, it is possible that the shaft is "sealed" and the cooling water isn't entering to do it's job. Likewise for the cutless bearing that is "fluted" in order for water to pass thru and cool the shaft.
Sometimes , a painted shaft will cause it. If you painted up to the thru hull, it is possible that the shaft is "sealed" and the cooling water isn't entering to do it's job. Likewise for the cutless bearing that is "fluted" in order for water to pass thru and cool the shaft.
Is it really too hot?
See earlier thread just the other day on this. Two things: nut too tight, misalignment lf engine and shaft. see the link
See earlier thread just the other day on this. Two things: nut too tight, misalignment lf engine and shaft. see the link
Reply to stuffing box dilemma
Well here's what i know. I replaced the shaft, cuopling and the stuffing box assembly. Did all this on my own and everything back in fairly well aligned. I then hired the yard to re-align the engine to the shaft. (this required four new mounts) I can only assume tha the engine and the shaft were lined up because I didn't do that myself. I'm one of those guys who hates water in my bilge but I guess it sound like I need to loosen the nut a bit more. Also can any one say how hot is too hot? I always heard that it should be "warm to the touch" Can any one be more definitive? Thanks! Tom
Well here's what i know. I replaced the shaft, cuopling and the stuffing box assembly. Did all this on my own and everything back in fairly well aligned. I then hired the yard to re-align the engine to the shaft. (this required four new mounts) I can only assume tha the engine and the shaft were lined up because I didn't do that myself. I'm one of those guys who hates water in my bilge but I guess it sound like I need to loosen the nut a bit more. Also can any one say how hot is too hot? I always heard that it should be "warm to the touch" Can any one be more definitive? Thanks! Tom
How warm is warm
Having just put a new conventional bronze stuffing box on my H28.5 (and cutless bearing) on my boat over the winter, I'm still in the process of adjusting it to drip a few drops per minutes while running in gear and none when out of gear or the engine is off. I'm also trying to define "how warm is warm." After running my engine for a while, you ought to be able to touch the metal and rubber part of the gland, with or without the engine running (carefully)and feel how warm it is "comfortably." The shaft will also be about the same temperature to the touch. If you cannot, that is, you would pull your hand away because either or both are too hot, you know you then would have a problem (with the compression nut being too tight, the packing material being the wrong size, the shaft/engine being misaligned, etc.)This is easier to determine than to describe. You'll know it when you feel it.
Having just put a new conventional bronze stuffing box on my H28.5 (and cutless bearing) on my boat over the winter, I'm still in the process of adjusting it to drip a few drops per minutes while running in gear and none when out of gear or the engine is off. I'm also trying to define "how warm is warm." After running my engine for a while, you ought to be able to touch the metal and rubber part of the gland, with or without the engine running (carefully)and feel how warm it is "comfortably." The shaft will also be about the same temperature to the touch. If you cannot, that is, you would pull your hand away because either or both are too hot, you know you then would have a problem (with the compression nut being too tight, the packing material being the wrong size, the shaft/engine being misaligned, etc.)This is easier to determine than to describe. You'll know it when you feel it.
Another possibility is silt or fine particulates
getting sucked into the gland. This would certainly add resistance to the spinning shaft that could cause 'extra' heat. I think that the link (mainesail sutffingbox) that David posted even mentions something about this. I have touched my stuffing box after the shaft was spinning for a while and did not find it uncomfortable to the touch. If it gets hot enough to evaporate water (212F) then you really have a problem. If it is merely warm to the touch (eg., > 98.6F) but does not feel hot or uncomfortable it is probably ok.
getting sucked into the gland. This would certainly add resistance to the spinning shaft that could cause 'extra' heat. I think that the link (mainesail sutffingbox) that David posted even mentions something about this. I have touched my stuffing box after the shaft was spinning for a while and did not find it uncomfortable to the touch. If it gets hot enough to evaporate water (212F) then you really have a problem. If it is merely warm to the touch (eg., > 98.6F) but does not feel hot or uncomfortable it is probably ok.
If water is dripping..
and the shaft is still too hot my guess would be that your flax ring joints are aligned and not off set. Perhaps you meant them to be off set but never seated them before you twisted the nut on to keep the joints off set. How many rings, which direction did you make the cuts, how did you make the cuts, what flax are you using etc. etc. these answers may help us to help you. Either way the nut is still to tight if it's getting that hot & the water must be sneaking through the joints in the flax but still not cooling the rest of the box. Your flax size may also be to big? Run it for at least ten hours though before you decide to repack some of this stuff takes time to settle in.. I think my stuffing box link was already posted http://www.pbase.com/mainecruising/stuffing_box but here it is again. It will show you how to cut the rings and how to seat them before spinning the nut on..
and the shaft is still too hot my guess would be that your flax ring joints are aligned and not off set. Perhaps you meant them to be off set but never seated them before you twisted the nut on to keep the joints off set. How many rings, which direction did you make the cuts, how did you make the cuts, what flax are you using etc. etc. these answers may help us to help you. Either way the nut is still to tight if it's getting that hot & the water must be sneaking through the joints in the flax but still not cooling the rest of the box. Your flax size may also be to big? Run it for at least ten hours though before you decide to repack some of this stuff takes time to settle in.. I think my stuffing box link was already posted http://www.pbase.com/mainecruising/stuffing_box but here it is again. It will show you how to cut the rings and how to seat them before spinning the nut on..
If it's hot, it is too tight. The dripping may
come from a leak of an improperly seated or damaged packing. Replace the packing and re-adjust. lcy
come from a leak of an improperly seated or damaged packing. Replace the packing and re-adjust. lcy
If water is dripping.. response
The box was repacked correctly as I have done it several times over the years. I used anew type of packing that was more expensive and black in color. I believe it has teflon or kevlar in it. Any way I wouldn't say it is boiling hot but is hotter than "warm" to the touch. I guess I loosen it some more but I hate the thought of too much water trickling in constantly. The engine has only been run for about 1 hour since the boat was launched so I guess the flax could be "breaking in". It is a new shaft/coupling/stuffing box and the yard aligned the engine after it was launched. I guess it's good that I installed a new bilge pump this spring huh? Tom
The box was repacked correctly as I have done it several times over the years. I used anew type of packing that was more expensive and black in color. I believe it has teflon or kevlar in it. Any way I wouldn't say it is boiling hot but is hotter than "warm" to the touch. I guess I loosen it some more but I hate the thought of too much water trickling in constantly. The engine has only been run for about 1 hour since the boat was launched so I guess the flax could be "breaking in". It is a new shaft/coupling/stuffing box and the yard aligned the engine after it was launched. I guess it's good that I installed a new bilge pump this spring huh? Tom
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