HOW LONG WILL THE SEAL LAST?
Tests have shown that 1000 hours can be expected. After that, a slight wetting of oil on the lip seals with an occasional drop can be seen. Some users prefer to put an oil absorbent pad under the seal unit to monitor any leakage.
WHAT IS THE MAXIMUM RPM THE SEALS CAN RUN?
Most propeller shafts do not exceed the RPM listed below at cruising speeds. The lip type seals being used in the NORSCOT seal are rated at 3 times this RPM*
DOES THE SHAFT SEAL HOUSING GET HOT?
During the first 10 to 20 hours of running the temperature could reach 150 deg. F. After run-in the temperature will stabilize at 120 deg. F. or less. The seals are capable of operating at 325 deg. F.
WHY DO YOU SUGGEST PUTTING A CHAMFER ON THE COUPLER END OF THE SHAFT?
This is standard practice for shafts using lip-type seals, so that a special tool is not required. We still advise using the installation tool that is provided, even when the shaft has the proper taper or chamfer.
WHICH ENVIRONMENTALLY-FRIENDLY LUBRICANTS CAN BE USED IN THE NORSCOT SHAFT SEAL?
The ideal lubricant is always a light-viscosity oil. ATF is the highest performing lubricant used in the Norscot Shaft Seal and only uses 2-3 drops of ATF every 5-10 miles while the boat is running, slightly more in a heavier sea state. No fluid is used while the boat is at rest.
You can use fish oil, vegetable oil, or a biodegradable synthetic oil.
However, we cannot guarantee the performance of these alternative oils. Seals could break down sooner and the housing could run a little hotter than by using ATF.
IS THERE ANY LEAKAGE OF TRANSMISSION FLUID?
There are no two installations that are identical, but some transmission fluid (ATF) can be expected to weep out under the two rear seals. This is desired for positive lubrication of these seals. The ATF level in the reservoir could lower as much as 1″ after 100 hours of cruising.
The front seal should not “weep” or drip into the bilge for several hundred hours of running unless the shaft is worn, scratched or marred from previous use. Relocating the seal (plus or minus 1/8″ or so) on the shaft will usually remedy this.
There should be no weeping of transmission fluid when the shaft is not turning.
HOW CAN I BE SURE THE UNIT WILL FIT PROPERLY OF THE SHAFT?
After the shaft has been chamfered, de-burred on the keyway, and finished with an emery cloth per the instructions, the seal housing should be lubricated internally and slid on the shaft, making sure it slides and rotes freely.
HOW LONG DOES IT TAKE TO INSTALL THE SEALS?
The shaft seal installation takes no longer than a conventional stuffing box, and does not require any adjusting after installation.