How To Fix A Spun Prop
America's Definitive Marine Engine Magazine
Learn How to
Diagnose and Repair
a Spun Outboard Motor
Propeller Hub
Hither's How to Definitively Determine When an Outboard Motor'south Propeller Hub is Spinning in its Bore and How to Set it
The lowly propeller provides frontwards move. At least until bad things happen to a good propeller. Y'all would think the penalty propellers endure when they whack into an inanimate object would be a death sentence. Merely even when a propeller hub spins, or a blade curls back at a sickening angle the damage
Beyond collision, another culprit is fouling the propeller with someone'south abandoned dock line. When it wraps around the propeller the engine keeps turning the propeller shaft but the propeller is locked up tight. What happens adjacent isn't pretty. The rubber hub breaks loose from the metallic hub and begins to spin in its bore at 1000- to 2000 rpm. As a event not all the engine torque converts into forward thrust and you begin to find decreased dispatch and tiptop speed. The solution is equally simple as the bounding main is table salt: Replace the hub. Depending on its size a propeller can exist reconditioned for as little as 30 to 100 dollars. Aptitude blades toll extra.
How Can Y'all Tell The Propeller Hub Is Spun?
So how do you know definitively that the propeller hub is spun? Brainstorm by removing the propeller and examining it. Look closely at the condom hub for telltale clues, anything from subtle to dramatic signs of failure. The hub might be twisted or fifty-fifty wait melted. Another method is to use a brawl pein hammer and a center punch. Pein a dot on the metal splined hub and side by side on the mating surface of the propeller proper. Reinstall the propeller and become for a ride. Run the engine under load. Merely idling dockside may not flow enough torque to claiming the hub. After a few minutes remove the propeller and examine your handiwork. If the dots no longer line upwardly, then the rubber hub is spinning in its bore.
So how to yous replace a spun hub? That'due south easy: Get out your debit or credit card. This is not a exercise-it-yourself projection. Propeller shops utilize a hydraulic ram and many tons of pressure to press the bad hub out of of its bore. It is then unceremoniously tossed in the trash heap, or more than properly, the aluminum or stainless steel recyling bin. A shiny, new hub is pressed in place, carefully. To ease the interference fit it is liberally lubricated with a spray of soap and water.
Some new wave propellers dispense entirely with the venerable pressed hub system. In its identify are replaceable hubs with a different hub available to fit each one of the spline patterns required for the different brands of outboard motors and stern drives. In the unlikely result a hub is ever damaged unproblematic accept off the bicycle, lift out the wrecked hub and throw it in the trash bin. Insert a new hub and yous are back in the h2o in matter of minutes. Beyond the quick set, what is really nice about the system is the mode you can switch from ane pitch propeller to another. That is invaluable for a boat that pulls double duty as a fast flyer or a ski tow boat. No matter what kind of propeller you accept information technology'southward a skillful idea to have a spare onboard.
Marine Engine Lay-Up Volume:
A Step-by-Step Guide to Decommissioning
Inboards, Stern Drives and Outboard motors
This pocket-size book features notes on how to service, diagnose and repair Outboard Motors, Stern Drives and Inboard marine engines. Coverage includes: wintertime lay-up and bound commissioning procedures; tune-ups, carburetor rebuilds and h2o pump repairs.
It also features a special section with forms to record work completed. Be advised this is not a shop transmission, only instead a marine mechanic's notes on how a DIYer tin accomplish these otherwise expensive procedures on his own.
About the Author
The author is a manufacturing plant-trained marine mechanic and service manager who, every bit a contributing editor, wrote most marine engine technology and repairs for Motor Boating magazine for three decades every bit well as contributing stories to Pop Mechanics, and various Boating and Yachting magazines in the US, Australia, Singapore and Brazil. He has plied the trade in the Caribbean, Iowa, Arizona and California.
Source: https://marineenginedigest.com/diy/diagnose-spun-propeller-hub.htm
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