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Ouch! That motor shaft ain't happy.
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Catching Air! -
I was happy that I didnt lose my prop, I already lost one on this boat...not so happy about the motor. Its hard to tell with the naked eye, but I think *maybe* the shaft on the motor isnt true anymore. It may have a slight wobble.Comment
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Yeah that really sucks.Catching Air!Comment
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Yeah, at first it looked like the motor mount broke loose and the damage came from that, but after looking at it at home its pretty easy to see that the shaft/tubing got so hot it basically welded itself together, and then ripped everything apart. The bent cable coming out of the motor smacked the positive battery wire and unplugged my battery so at least that stopped it from whipping around and tearing up the hull (no damage to hull at all, which is cool, since I paid a ton for this hull).
Embarassing as it is to admit, I thought the cable was making a weird noise about 15-20 seconds before it broke...kind of a whistle...too dumb to stop running though. This was by far the loudest cable break Ive ever heard.
Im not sure where to go from here. I guess maybe 1/4" tubing and another .187 cable?Comment
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So you are just running the flex and brass tube correct?Catching Air!Comment
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Yes.
I annealed the tubing and put a 3/16" rod in it before I bent it to keep it true. There wasnt a tight spot in the tubing or anything, but its such a good fit that there is almost no room for grease. I greased it well before I ran it, but its still pretty much metal on metal. Maybe it would work at a lower rpm, Im not sure...not at 35,000+ though.Comment
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oh no! 7/32" Works good, but only with very minimal bend in the tube. Did you support the tube portion inside the hull? It looks like a long length of unsupported tube. A little vibration can cause cable whip and it will rip the stuffing tub apart like that. That's crazy it bent the motor shaft like that!
Sorry bud.Comment
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I planned on adding a support later this week but wanted to get her in the water. I tested it before running it and the tube got warm just running on the bench. I thought maybe it wouldnt be a problem in the water but like I said should have went with my instict and just changed it.
What do you suggest rum? 1/4" tubing??? I could put that 1717 in there next time but I dont really see an advantage. I dont think the 1520 had a problem turning the s220. Im thinking now maybe a 1518 on 6s...Comment
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Did you sand down the cable a little. I run the same tube and cable in my Bittburger and sanding down the cable slightly makes a big difference, of course I'm not running anywhere near as many rpm as yours. (1668kv, 4s). In my hydro I'm running a .187 cable in a 1/4" tube and am happy with it so far.(2200kv, 4s) If nothing else it seems to hold more grease longer. And it does not seem tight or to bind at all.
MarkComment
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I didnt sand it down Mark, it never occured to me. I think I will just order some 1/4" tubing and another 3/16" cable though. The sanding might work but I dont want to go through this again if it doesnt. I was thinking before it broke about how this boat could be fast, but "trusty", meaning it wouldnt need alot of maintainance and it would always run. My thoughts were obviously premature.
Hopefully with the new cable/stuffing tube it can be trustworthy. I am thinking of putting a 1518 in it this time for a little more RPM (1800kv) and doing a couple speed passes on 6s, then running it regularly on 5s, maybe even 4s. Its either that or the 1717 and a bigger prop.Comment
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Thats hurts Keith. Sorry to see that to such a beautiful boat.Comment
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I went through the same thing when I first got my Bitt. Broken gears(it had a gear drive trans), 2 snapped flex cables, smoked ESC, broken motor mount, etc...) Finally at the end of the first season I ended up gutting it putting a lower kv motor in getting rid of the gears and redoing the whole driveline. By swapping out the motor I can turn a larger prop, temps are nice and cool and it's just as fast. I hate to say this and jinx myself but I have not put another penny into it in the last two seasons. It's not stupid fast but fast enough but most importantly (to me) depenable. I can always up the battery cells if I want more speed, but since I've been running my Stealth hydro my son has pretty much taken the cat away from me. But I still get to sneak in a run with her from time to time. LOL
MarkComment
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When I got mine I didnt like the "s" bend in the stuffing tube, or the mess where the motor mounted, but I ran it anyway. After it broke that flex I decided to take it all out and redo it. I think I was on the right track, and I can say this combo ran quite well, just a problem with the stuffing tube size for my app. I'm kind of thinking along the same lines as you, I just dont know if 4s on a 1600kv will be enough for me or if I should put my 1800kv in it. I want to hit 70mph with this boat first... I dont think it will be much of a problem really, it stays on the water quite well and I dont think Im that far away now based on what I saw today. I think I was in the low 60's on 6s (guessing, glad I didnt have my GPS in there!), so the 1520 on 7s or the 1518 on 6s might get it there.
Once I get the speed I want out of a boat I usually get pretty bored with it, thats when it would become a 4s/5s cruiser.Comment
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Keith;
Should have listened to yourself.
Now you know (unfortunately) why 7/32" tubing is used for strut bushings in Speed master
struts.
Just a bit TOO tight for flex shaft use .
Looks like you have a few hrs. work ahead of you. :-(
CarlComment
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