Q: Greetings Mr. Lee, I am addressing this to you because I know that a lot of folks read your column, you are most knowledgeable on engines. Late last October I was starting a new 4 cycle, 1.50 engine for the first time. I had a high quality aluminum spinner attached with the standard adapter that I’ve used many times. The engine backfired and the prop, adapter,spinner etc almost exploded off the shaft. It happened so quickly I could not believe what had occurred.
However there was blood all over the garage floor instantly and my wife was frantic, as she was holding the a/c. I was in the hospital two days as the local surgeon would not touch the wounds. Several ligaments were cut and one bone fractured. I am still not 100% with the hand. To shorten the story I now find that Tru Turn makes a double locking adapter that I am sure would have saved me all this mess.. Most shafts as I have discovered are not long enough to take the main & jam nuts that comes with the engine plus the spinner adapter. Tru Turn’s product is a double jam nut set up and the jam nut is internally threaded to receive the 10 -32 screw that retains the spinner. This jam nut has a slit cut perpendicular to the shaft that not only jams the main nut but appears to me to squeeze the shaft as it is tightened. It may be worth while for your readers that use 4 cycles, to ask for this kit. I have no idea how long it has been on the market. A great product IMHO. Always enjoy your column.
A: Sure sorry to hear about your accident. I do find it strange that you suffered so much damage to your hand. I have had any number of 4-strokes back fire during starting loosening the prop, but never had the prop fly off with the force yours must have done. I will be running your letter in an upcoming column. I also intend to contact the Tru-Turn people and get one of the adapters you mention for an included picture.
Thanks for sharing your experience.