Cable vibration

[Gary]

One thing I have noticed with cable drives is that they vibrate like crazy on the bench test. Even with no prop it will suddenly go into a vibration until you change throttle inputs. Cable is a .187 in a 1/4 tube that is 10" and has a very gradual bend. Testing on a mock set up .... the next size smaller tube its perfect but is to tight and will get hot. Anyone have an idea on how to prvent this? I know it seems to be gone when under throttle in the water but I would think there is power to be had if it was perfectly smooth. Mabe im just grabbing at straws who knows.

[Fluid]

Yes I do, stop "bench testing". Never run your boat on the bench! There is no upside to doing this and only problems to induce. You are using the right parts, now only run the boat in the water - problem solved as the water will dampen the "vibrations". Just a blip of the throttle to confirm the motor works and is spinning in the right direction, then in the pond.


.

[785boats]

The cable itself is very seldom the cause of the vibration unless it has a kink in it.
It could be an out of balance prop.
It could be worn bearings in the strut/stinger.
It could be a bent stub shaft.
It could be a loose motor mount.
It could be that the motor shaft does not line up with the shaft.
It could be that the hex flex coupler is off balance or off center on the motor shaft.
Is there plenty of grease in the shaft?
Check these things out first before you blame the poor old piece of flex.

As advised by Fluid. Don't bench test.

[carlcisneros]

WHAT FLUID SAID.

when you run a motor on the bench WITH the cable attached, there is no load on the prop/shaft assembly and the
poor flex shaft goes into warp whip. (so to speak.)

The same thing happens on nitro and gas powered boats as well.

[iridebikes247]

No good definitely need load on the prop as the other guys said.

[detox]

Sometimes when you think you have everything concentric and balanced good, you will still hear that dreaded vibration. Like fluid said " never run your boat on the bench"

Check for excessive collet runout where cable enters stuffing tube. I use a little bit of never seize on threads of collet then tighten collet in steps at different locations of collet nut until collet is pretty darn tight on cable. Most of the time i can get my collet/cable runout under 1/32 inch.

Heres how i tighten collet: Snug down collet nut, then rotate motorshaft 180 degrees and tighten collet nut again, then rotate another 180 dgrees and tighten nut down tight. These steps help me achieve better runout.

Lots of cable grease helps dampen sound also. Especially water mixed in with your cable grease inside stuffing tube after a run.

[Gary]

I know never to spin a motor to high when testing. What I did was put a cheap motor and esc just to test it out to see how bad it is and was very surprised. But I now see that when it is in the water the cable is tighter because of the load and will be totally different effect in the stuffing tube.

[tlandauer]

Sometimes when you think you have everything concentric and balanced good, you will still hear that dreaded vibration. Like fluid said " never run your boat on the bench"

Check for excessive collet runout where cable enters stuffing tube. I use a little bit of never seize on threads of collet then tighten collet in steps at different locations of collet nut until collet is pretty darn tight on cable. Most of the time i can get my collet/cable runout under 1/32 inch.

Heres how i tighten collet: Snug down collet nut, then rotate motorshaft 180 degrees and tighten collet nut again, then rotate another 180 dgrees and tighten nut down tight. These steps help me achieve better runout.

Lots of cable grease helps dampen sound also. Especially water mixed in with your cable grease inside stuffing tube after a run.

The anti-seize on collet is one of the best tricks I learned here from Fluid, also that is how I tighten all my collets, always rotate 180* and tighten and repeat until it is tight. With the anti-seize, because there is no galling, when it is tight, you will know it, I don't have to worry about over tightening the collet nut.

[Southwest]

The first thing i thought of was the jaws in coupler were uneven in spacing. Next was cable needs replacing. Then i read where Fluid and Paul785 and another gentlleman told how he tightens down the coupler. We learn everyday, glad.

[Basstronics]

You will always have some runout. The more shaft put into the coupler will help reduce the effect to an extent. The tighter the coupler fits, the less the runout should be.

[785boats]

I don't know about you guys, but I find the best fitting & truest running collets to be the ones with the 2 set screws that oppose each other. Like these.

http://www.offshoreelectrics.com/pro...ct-ocfhe5mm187

The worst are probably the TFL cheapies that come in those RTR boats. They wobble terribly & don't even grab the cable half the time.

I know that most of you will have other preferences as to what runs truest. Maybe you could share.

[tlandauer]

I have good experience with these and also the 5mm to .150 both the long and short version. I don't like the four pronged Proboat collets, seemingly they go to the trouble to make four prongs but they are not always true and they are very thin, I have replaced all my Proboat ones with these Octura ones. I know someone once said even these are not 100% true, luckily I have not come across one yet. Those TFL look cheap even on the web site, at least to my eyes.

[grsboats]

Best collet used is from MBP..go to Rocketcity to watch the video...... no way to use another one on my riggers.Gill