Shaft Packing Installation

If the packing that is in the stuffing box is still in good shape,you might try measuring it to get an idea of the correct size. This will be an estimate as the packing may have taken a set. You can measure the distance inside the stuffing box from the wall to the shaft. This will give you a good idea of the size. You might call the boat builder if they are still around and try and get direction from them as to the size. Some builders incorporate the packing size information in the boat’s operating manual.

You can use a flexible packing extractor tool that looks like a cork screw on a flexible shaft. These extractor tools come in several sizes. The various tool sizes are listed below with the size of shaft packing they will extract. Some of the tools will cover more than one (1) size of shaft packing. Review the information to determine the correct size tool you require for your specific application. Now you have the correct extractor tool. Carefully stick the sharp tip of the extractor tool into the body of the old packing and twist the tool so that the cork screw tip engages the packing and you have a secure hold on the packing with the tool. Apply steady pressure and continue to pull on the packing until it comes loose. If you pull to hard or to quick, you might tear the old packing or break the tool’s tip off in the old packing. Once you get all of the old packing removed from the stuffing box, check to make sure the stuffing box is clean and free of any other foreign material.

No, do not add more shaft packing to a stuffing box that already has old packing in it. All your doing is forcing more material into the stuffing box cavity which will not accomplish much other then create more drag and more heat in the stuffing box. Do it the right way and clean out the old packing. Replace it with new packing of the correct size.

This replacement packing situation is a bit like buying oats. If you want them fresh and dry they cost more then oats that have been through the horse. Take your time, do your homework and do the job right the first time.

Common sense should prevail here, but alas tighter seems better to most boaters. Wrong!!!! Tighter is not better, in fact you should hand tighten to start with. Tie the boat off in the slip. Start the engine and let it run at idle. Engage the transmission and let it run for about ten (10) minutes. Now start to watch the drip and hand tighten until the drip stops. If you cannot stop the drip by hand, use a wrench and turn the nut very slow and very little until the drip stops. To much pressure on the nut is one of the major problems that causes a heat buildup in the stuffing box. Treat it gently.

You should use a shaft packing lubricant if you want to extend the life of your shaft packing and if you want to get better performance out of the new installation. Your packing will work without the shaft packing lubricant- it just won’t work as well or last as long. One of the better shaft packing lubricants is a product called syntef. This lubricant is not only a quality shaft lubricant it is also a sealant that reduces the amount of water that enters the stuffing box. The installation is simple. Wear a protective glove and simply coat the shaft packing on all sides with the syntef shaft lubricant. Then install the shaft packing as normal.

The number of rings that will fit into your stuffing box will be based on the space within the stuffing box. It is not necessary to fill the entire cavity with rings of packing. You need to leave enough space to effectivley secure the nut in place with more than one or two threads. Common sense would tell you that if you can get three rings in the stuffing box and you can secure the nut with three or four threads, then leave it at that and don’t try to put in a fourth ring of packing. Too many boaters try and put too much packing in the stuffing box. In this case more is not always good.

It is recommended for most applications that packing is cut straight to the center of the shaft. This provides for the smallest amount of frayed ends. Packing cut on a diagonal has a greater chance to unravel or not seat properly and is not recommended for medium and high speed applications. Precision in cutting your packing is critical. Use a very sharp blade for as clean a cut, as possible. Most packings will contract during break in and it is recommended that the packing be cut 1-2% longer than the measured length. The outside diameter of the packing is greater than the inside diameter, therefore, a straight cut on the shaft is actually a cut at an angle of about 20 degrees when cut on the flat. This assures that both the outside and the inside of the packing will butt together tightly. If cutting the packing on the shaft or on a piece of shaft kept for that purpose; wrap the packing firmly around the shaft and cut straight towards the center. If cutting on the flat, the inside length of the packing will match the circumference of the shaft while the outside length will be greater due to the thickness of the packing. Cutting at an angle of about 20 degrees is critical for a tight fit.