Stuffing box - prop shaft

[rustednail]

What kind of maintenance is required on the stuffing box/prop shaft on the R21EC? Or other models as well. This is the first inboard boat I have owned and want to make sure all is in order before launching.

I turned my prob through by hand and could hear an unusual sound, kind of like a roar. Is that normal? Does water assist in lubricating?

 

[rt11002003]

In general, there are two types of stuffing boxes. One is the dripless type and the other is the adjustable (drip) type found on our R-21 ECs. Each has its pros and cons. I prefer the drip type, simply a matter of preference on my part. 🙂

The adjustable type has a packing inside the housing and as one turns the adjusting nut that packing is compressed around the shaft and lessens the flow of water around the prop staft. Notice my use of the word "lessens", one must have a small amount of water dripping, perhaps a couple of drops every 10 to 20 seconds when the shaft is rotating. If too tight the shaft can overheat, if too loose a boat can sink. :shock:

I suspect the noise you hear is the packing rubbing on the shaft. There are different types of packing available, some are smoother than others and will make less sound. Yes, the water helps lubricate the stuffing box.

 

[henrym]

You did not mention if the boat was in or out of the water when the "unusual sound" happens. If it is out of the water, the noise you are hearing is probably coming from a dry cutlass bearing causing the shaft to chatter while being turned by hand. When the engine is running, water is pumped into the rear of the stuffing box where it can cool the wax impregnated flax packing in the stuffing box, assuming that the stuffing box adjusting nut is not too tight, the excess water will flow down the shaft log and out through the cutlass bearing, lubricating and cooling it in the process.
If the "unusual sound" occurs while you are under way, it can be caused by foreign matter lodged in the cutlass bearing, such as sand or barnacles etc. This is assuming the stuffing box wax impregnated flax packing is not dry and worn out, and the adjusting nut is allowing a slight drip while under way. See below: Flax Packing and Cutlass Bearing

Henry

 

[rustednail]

Hey,

Thanks for the wonderful information! Yes, the boat was out of the water. I was doing a walk around inspection as preparation for launching. Unfortunately, I ran into another little problem on my boat. The bilge pump keeps blowing fuses. I have an email into Johnson Pumps, waiting for warranty info, etc.

I didn't want to make the first launch of the season with a malfunctioning bilge pump. It is better to be on dry land wishing I was out in the river, then in the river wishing I was on dry land. Didn't want to risk it.

May go ahead and buy a replacement pump while waiting for warranty issue to be resolved, and once it is replaced, will mount a second pump as a just in case.

Again, Thanks for the insight!
Bri