When installing a replacement propeller, it is very important to get the retaining nut tightened securely. Many boat owners have been surprised to find their replacement propellers sinking to the bottom of a lake due to a retaining nut coming loose. After removing the original outboard motor's propeller, it is recommended that the propeller shaft be thoroughly cleaned with a quality brake cleaner to remove any grit and dirt. A thin coating of petroleum jelly will allow easy removal of the replacement propeller in the future should the need arise to do so. Making sure to slide the replacement propeller over the key way in the shaft and tightening the retaining nut to the recommended torque will ensure a solid and stable propeller for future boating pleasure.
After striking a large rock or stump, it is often necessary to swap the original propeller of an outboard motor with a replacement propeller. Original equipment propellers are very strong, but they can fail and break when encountering a solid object in the water. While it seems to be a very simple and straightforward procedure to change and install a replacement propeller, it can often become confusing. Many propellers are supported on the drive shaft by a series of washers and spacers. It is imperative that these be replaced in the same order as they were removed to avoid possible damage to the shaft's bearing.
To keep things organized, it is recommended that the washers and spacers be stacked in the same order as they come off of the shaft. Replacing them then becomes as simple as placing the entire stack on the shaft in reverse order prior to installing the replacement propeller. The parts should be wiped clean and checked for wear as they are removed. Any worn washer should be replaced with a new unit. It is also very important to examine the propeller shaft and remove any fishing line that may have become wound around the shaft. Even a short piece of monofilament fishing line can destroy a bearing and seal if allowed to remain wound around the shaft.
When installed properly, a replacement propeller can perform as good or better than a stock piece. Taking time to ensure every piece is installed properly is the key to a successful installation. Most retaining nuts used to secure a propeller are drilled for use with a cotter key. This key goes through the nut and the shaft to ensure it cannot back off. It is always recommended that a new key be used every time a replacement propeller is installed.