Are there different grades of flex shafts...stronger... types of metal? and what are the most perfered?

I've run flex shafts from lots of sources including Competition Marine Design (Andy Brown), Aeromarine, Octura, and commercial Homelite shafts. The main reason any broke was corrosion caused by not cleaning and lubricating the shaft. I also found that Mercury Quicksilver 2-4-C grease does a great job of protecting the shaft and is available everywhere. I'm sure there are other greases that will work as well. Another cause of failure can be binding from too quick shaft bends. However, I've been experimenting with an outboard lower unit that has a much more severe bend than the commercial units. There have been problems, but shaft breakage hasn't been one of them. There are differences in flexibility due to different wire sizes, but I've not seen differences in durability.

Lohring Miller

Thanks,
My problem is...in my cat i can grab the end of the prop and twist it about half way around before the motor starts to turn over. Seems spongy?? In my Hydro there is almost no twist before the motor turns over and the shaft is almost twice as long. In my cat the shaft is only 12inches long. I want to replace it for obvious reasons. By the way it is the square shaft didnt know if it matters....

also i did check to make sure that the wire twists were being twisted together(with the direction of the motor) and not done

Dave

One of the tests we used with K&B outboard shafts was to twist the prop while holding the flywheel. If it twisted more than 1/4 turn, the shaft probably had broken wires and needed to be replaced.

Lohring Miller

Thanks

The shaft needs replacing Think im going with the Aeromarine???

G'day Piratefish, what type of cat is that?, looks identical to a chinese cat I have just bought. Tasman

YO Tasman

its a Stryker cat from RC Boat Works its about ten years old. They have a couple of new designs now.
Yesterday i drove it into the rocks and chipped up the front sponsons pretty bad:(

Piratefish

Ps it runs great... like its on rails

Ive had great luck with Speedmaster shafts, and very bad luck with Hughey shafts. Seems to me the Hugheys are wound too tight...

Will, Ill give them a try. I m running the square shaft. i can't seem to find them without the drive shaft connected. My flex shaft is about 12in and will need to cut it down.

If you are running square drive, try visiting your local small engine shop...they often through out old weedwhackers in which the shafts are still perfectly good. It's a cheap source for flex cables. Just make sure they are really 1/4\"...some brands used slightly smaller diameter cables.