Zelos 36 stuffing tube is burning hot

So i first got my boat a few months back and after a few runs i melted the teflon liner as the heat traveled up the stuffing tube the plastic mount near the motor melted and spun the stuffing tube. So i did all the photos for warranty and was told its my fault because i didn't grease the shafts:unsure: So i glued it all back together but always had extreme burning heat on both sides of the stuffing tube after 3 min runs. So i worked out its coming from the bends in the stuffing so i ordered some 3/16 tube that fitted perfectly inside the standard tube and re sleeved from each end leaving about a 25mm void for the bend in the standard tube. Then i used some normal OS diameter teflon liner for the new stuffing tube glued in with Loctite so it wont spin in the tube. I was able to do this because they use there own larger special size stuffing tube and teflon liner as you might have notice.. Straight away there was less resistance when putting the flex cable in and no heat what so ever after some hard flat out runs. No doubt there is some poor manufacturing within and just love how they pass the buck and say you should grease your shaft every run lol I thought i might share this as it might help others with the same problem or even if you wanted the option to run the bigger inside dimension teflon for less resistance as i had 2 options now i was using a normal size tube.

So you are not re-greasing your cables after every run?

The manual clearly states to lubricate the drive shaft and all moving parts after every 20 minutes of operation. No matter what size or type of liner is used, lubrication is still required. This is true for all boats, not just the Zelos. The OP went to a lot of trouble replacing parts when all that was required was a little bit of normal maintenance. The latter is how most users avoid the problem.

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Originally Posted by fweasel

So you are not re-greasing your cables after every run?

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No not every run. I have 2 sets of batteries and get about 4 min each = 8min run than go home and use the special Horizon Dynamite marine grease i got with the boat. The guy in the hobby shop was very good and clear when selling this boat as he runs one regularly but i have built a gas boat years ago raced nitro buggy's also been flying 3D heli for years so not a complete noob in the rc game.

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Originally Posted by Fluid

The manual clearly states to lubricate the drive shaft and all moving parts after every 20 minutes of operation. No matter what size or type of liner is used, lubrication is still required. This is true for all boats, not just the Zelos. The OP went to a lot of trouble replacing parts when all that was required was a little bit of normal maintenance. The latter is how most users avoid the problem.

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Exactly 20min not every run. Maybe they need to update.

Also had trouble with the teflon spinning in the tubes. Causes massive heat build up and happened straight out of the box. Stopping the teflon spinning - as you did - is the only way to fix the heat issue in the tubes. Seems like a real problem with this boat. Not sure if the new Geico is different....

I found the stock tubes nearly kinked in the center. You can your fingertip down the curve and feel this. The liner also does not appear to be a genuine Teflon. It has a much whiter and less blue appearance. It also seems thicker.

A simple way to stop liners spinning in a few minutes is to bind the outside of the liner in 2 or 3 places along its length with ptfe plumbers tape, just enough wound around the liner to make a tightish fit when sliding back into the stuffing tube. This method is so simple & is 100% effective.

but how do you get the old liner out of tube?

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Originally Posted by dbgryche

but how do you get the old liner out of tube?

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You can pull it out on the motor side of the tube. You'll probably need to remove the collet to make more room, and possibly remove the entire motor for more clearance.

i had to thread a bolt into the liner a bity but got them out. i was hoping there would be damage to them causing the drag i'm having with miss G but ill install new liners and waiting for prop shafts so i can make a couple new flex shafts and see it the combination of replaced parts will help get her back up on plane

I had the same problem on my Miss Geico last year after 3 min's steam was pouring out and I couldn't keep my finger on the stuffing tubes due to the heat and flex shafts were greased too. Simple fix for me was I pulled the OEM liners out, cut new 1/4" tubing to same length as OEM tubes, heated new tubes to Red and pushed them back inside the OEM tubes. Greased the flex shafts and pushed them back into the stuffing tubes and they lined up with couplings. I do not use liners anymore.

She's hauling the mail with Super Geico props and no more over heating.

Great solution. Simply replacing those thick PTFE or whatever-they-are liners with teflon would help too.

PTFE is Teflon, but I’m not convinced that all makers use decent quality Teflon for liners, I suspect some use nylon etc. Too, many of the plastic liners grab the flex cable and spin inside the outer tube generating lots of heat. I quit using it decades ago, for 3/16” cable going with 1/4” brass tubing and no liner. Works great, I set many SAW records without liners, just be sure to use a good lube which includes an EP additive. BTW, in spite of what some say, there is no need to heat the brass tube to bend it.




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I believe that this "re sleeved from each end leaving about a 25mm void for the bend in the standard tube." and this "I found the stock tubes nearly kinked in the center." are the issue here. For maximum efficiency and lifespan the stuffing tube should have a gentle curve nearly from end to end if you put all the bend needed for a cat into only an inch of length that is a very tight bend radius and the energy spent moving those flex strands over themselves will heat it up. As we are seeing here sometimes it will be enough heat to melt the liner, sure you can mask the issue by removing the liner so it wont melt and cause further problems, but you will still have an inefficient driveline and the only way to fix that is by replacing the stuffing tube with one that has a gentler curve.

Teflon is just DuPont's trademarked name for PTFE, replacing PTFE for Teflon will do nothing for your boat, the only difference is that your wallet will be a little lighter and DuPont's a little fatter.

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Originally Posted by NativePaul

I believe that this "re sleeved from each end leaving about a 25mm void for the bend in the standard tube." and this "I found the stock tubes nearly kinked in the center." are the issue here. For maximum efficiency and lifespan the stuffing tube should have a gentle curve nearly from end to end if you put all the bend needed for a cat into only an inch of length that is a very tight bend radius and the energy spent moving those flex strands over themselves will heat it up. As we are seeing here sometimes it will be enough heat to melt the liner, sure you can mask the issue by removing the liner so it wont melt and cause further problems, but you will still have an inefficient driveline and the only way to fix that is by replacing the stuffing tube with one that has a gentler curve.

Teflon is just DuPont's trademarked name for PTFE, replacing PTFE for Teflon will do nothing for your boat, the only difference is that your wallet will be a little lighter and DuPont's a little fatter.

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Hey Paul what boat are you talking about? The thread is about the Zelos36 and Miss Gieco 36. The stuffing tubes are almost straight.

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Originally Posted by 1coopgt

Hey Paul what boat are you talking about? The thread is about the Zelos36 and Miss Gieco 36. The stuffing tubes are almost straight.

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One plenty of those production hulls, the bends in the stuffing tubes were too severe and the primary cause of the overheating and friction issues. Cheap stock flex cables with misaligned flex to prop shaft joints are another cause.