schreeching flex shaft

[UrbanPoser]

Hey all. Finally go my MG out for her 2nd maiden voyage today, and she was handling great. Flipped her twice, and submarined her once. All I gotta says is, you GOTTA tape the hatch. I was thinking of not doing it since it's a pain in the butt, but it was totally worth it. Not a drop of water inside. Great fun!

Anyway, I was wondering. When I have the boat on the bench, and I run the throttle, the flex shaft makes this awful screeching sound like it's vibrating badly. I have the stop shaft and prop in it. But when I was running it today at the lake an goosed the throttle when it was onshore (prop spinning in the air), the screeching was gone momentarily (ran smooth and quiet) and then the banshee came back. Is this normal? Or do I have a bum shaft? Seems with the teflon sleeve and grease, it should run silently.

[JackBlack26]

That squealing sound is the the Teflon liner spinning with the shaft. If you have not done so, grease the shaft. Mine did the same and that fixed it.

[jac4412]

Urban, keep an eye out you don't want to be running your boat when it isn't in the water (unless its for a brief test).... not good for the ESC. But yes, it's most likely a shaft which needs to be greased.. pop it out and grease it, that will smooth out the flex and get rid of your noise. If it continues then you've got something in contact with the shaft which is not good.

Also, youre going to want to grease you shaft every few runs to keep in 100% shape.... dumping her and runtime will reduce the grease on the shaft.

[wppracing]

I used to grease the flex shaft every hr or so. BUT yesterday the boat stopped in the water. The shaft froze to the brass bushing in the prop strut. I was able to pull the shaft and bushing out and remove the bushing from the shaft. I cleaned the shaft and pressed the bushing back into the prop strut. It is now working correctly again. I also called Horizon Hobby and talked to the tech dept. They are sending all the parts I needed to fix the issue, new flex shaft, liner and prop strut at NO CHARGE.....

[UrbanPoser]

I have been greasing the shaft, but perhaps not enough. So, I just pulled the shaft, and out of curiosity pulled the teflon liner to see if it had any damage. It looked fine, so I tried pushing the liner back in the brass tube from the motor side It slowly slid in with much effort, and now I can only get it back in about 80% of the way I tried warming it with a hair dryer, and it just won't budge - it's a tight fit. So I said, ok, I have a spare shaft and liner from Kintec, so I'll just put that bad boy in. That teflon liner won't go in more than about 1/2"! Is there any trick to installing these liners? Do I need a special tool or something?

[lectriglide]

Did a search and found 2 ways.
#1 was put it in the freezer. Didn't say how long but it did say you have to be fast installing it or it would "thaw".
#2 - Make sure you have plenty of excess length to start with [ about 2" on each end], then grip both ends in pliers or vice grips & strrrretch it out; slide it in & trim the ends.

Good luck - let us know how it turns out.

[tiqueman]

I use the stretching technique often and it works nicely. Even at lenght, yo can grip it w/ your fingers and pull it. I typically put it in both hands, holding it in the middle of the liner with my hands touching, and pinch it as tight as possible and pull, it will slide through your fingers and you get more of an even stretch.

As for the bushing. A lot of folks have had issues w/ it. I remove and grease the shaft every 2 runs. I seized mine to where it would not come apart. I got the parts out of the strut and replaced it w/ the aeromarine bushings and havent had a problem.

Also on that note, even well greased, a bushing will often make that screaching sound out of the water, as will brass cartridge bushings. Keep things well lubed and everything will be fine.

[UrbanPoser]

Thanks for all the good advice, everyone. Freezing the liner helped, but not much (and it warmed up too fast to be practical). I found the stretching worked best. I only had about 1/2 inch to spare on the length, so I put nails about the same inside diameter of the lining in each end, griped both ends with pliers and pulled (the nails were to keep the tubing from crushing too much). After a couple of times it finally slid in. Finally.

I'll grease the hell out of it and keep greasing it, and see if that helps. I'll let you know what I find out.

Where can I get an upgrade bushing? Kintec seems to have them on their website, but there isn't a purchase button.

[makin' waves]

I heard you should go lightly with the grease on the stuffing tube and flex cable (just enough so it won't rust)

And then heavy on the grease in the shaft...

Tone
Tone

[wilsta67]

Hey all. Finally go my MG out for her 2nd maiden voyage today, and she was handling great. Flipped her twice, and submarined her once. All I gotta says is, you GOTTA tape the hatch. I was thinking of not doing it since it's a pain in the butt, but it was totally worth it. Not a drop of water inside. Great fun!

Anyway, I was wondering. When I have the boat on the bench, and I run the throttle, the flex shaft makes this awful screeching sound like it's vibrating badly. I have the stop shaft and prop in it. But when I was running it today at the lake an goosed the throttle when it was onshore (prop spinning in the air), the screeching was gone momentarily (ran smooth and quiet) and then the banshee came back. Is this normal? Or do I have a bum shaft? Seems with the teflon sleeve and grease, it should run silently.

you said its vibrating bad? have you changed the prop to a metal one? is it balanced?

[UrbanPoser]

It was just making a bad screeching sound. But once I replaced the teflon liner and re-lubed the shaft, it's been quiet. right now I'm using the plastic stock prop.

[sailr]

I quit using teflon liners a long time ago. Nuttin but trouble.

[wilsta67]

I quit using teflon liners a long time ago. Nuttin but trouble.

i agree! better off to slip another piece of brass tube in there to take up the space.