Watch this guy trash his U-joints!

[Friscoboater]

This is great. You can even hear the joints binding.


http://www.youtube.com/watch?v=xBqeOMZ3FtY

 

[lowkee]

Re: Watch this guy trash his U-joints!

I don't understand, why would revving it tilted ruin u-joints? Isn't that the purpose of them, to spin while bent? I can understand how straight u-joints would be under less stress than bent ones under load, but in neutral with no load?

I must not have an ear for that, as it just sounded like a revving engine.. which made me cringe anyhow, since I irrationally think only motorcycle engines should be revved for no reason

 

[RICHARD5]

Re: Watch this guy trash his U-joints!

I did that except I only goosed it once...a quick from idle to full throttle back to idle. Cost me almost $500 in parts.

http://forums.iboats.com/showthread.php?t=342639

 

[lowkee]

Re: Watch this guy trash his U-joints!

Wow, after reading that thread link, I learned something I had no idea about prior. I never knew the u-joints couldn't be revved while the outdrive was up. I'm still not sure if this applies to all outdrives or just some, but definitely scary to ruin such an expensive part so easily.

 

[scoutabout]

Re: Watch this guy trash his U-joints!

Ouch, Richard -- that was probably a bad day...

But for this guy -- I dunno -- it looks like it was in neutral to me as the prop never really got spinning that fast and stopped at idle. Probably just the viscosity of the (probably cold) oil causing it to turn a little. I doubt it did the joints any harm.

 

[Adjuster]

Re: Watch this guy trash his U-joints!

Your drive can be up but not all the way up in the trailer position. Too much stress on the joints even in neutral.

 

[fishrdan]

Re: Watch this guy trash his U-joints!

I must not have an ear for that, as it just sounded like a revving engine..

It took a couple of listens, but yeah, that doesn't sound good. Listen for the pops/bangs just before he idles it back down. Kind of sounds like a backfire,,, steel backfiring through aluminum

 

[tashasdaddy]

Re: Watch this guy trash his U-joints!

all outdrives, the drive shaft turns with the motor all the time, the shift is in the lower unit.

 

[fixb52s]

Re: Watch this guy trash his U-joints!

Ouch, Richard -- that was probably a bad day...

But for this guy -- I dunno -- it looks like it was in neutral to me as the prop never really got spinning that fast and stopped at idle. Probably just the viscosity of the (probably cold) oil causing it to turn a little. I doubt it did the joints any harm.

Those U-Joints are turning any time the engine is running. The driveshaft is directly connected to the engine. Neutral gear is in the drive itself, after the u joint.

 

[H20Rat]

Re: Watch this guy trash his U-joints!

I don't understand, why would revving it tilted ruin u-joints? Isn't that the purpose of them, to spin while bent? I can understand how straight u-joints would be under less stress than bent ones under load, but in neutral with no load?

I must not have an ear for that, as it just sounded like a revving engine.. which made me cringe anyhow, since I irrationally think only motorcycle engines should be revved for no reason

Ujoints have a fairly restricted range of operating motion regardless of load, 45 degrees is ABSOLUTE max for a u joint that is designed for it. (many will not tolerate anything close to 45 degrees before self destructing.)

 

[45Auto]

Re: Watch this guy trash his U-joints!

I don't understand, why would revving it tilted ruin u-joints? Isn't that the purpose of them, to spin while bent?

Go get your typical 3/8 socket set. Put a socket u-joint between 2 extensions. Now hold one extension level and start turning it while slowly increasing the angle on the other one. You'll feel the u-joint start to bind as the angle increases. The binding increases quickly once you pass a very small angle. You're doing the same thing to your drive when you run it tilted all the way up.

While it's possible to do and you may get away with it for a long time, don't be surprised when one of those u-joints breaks on you.

 

[scoutabout]

Re: Watch this guy trash his U-joints!

all outdrives, the drive shaft turns with the motor all the time, the shift is in the lower unit.

Aw, of course...I didn't think that one through. That'll teach me to post after my bedtime....

 

[mphy98]

Re: Watch this guy trash his U-joints!

soooo... what you are saying is that I shouldn't raise the outdrive in shallow water to get through? I thought that was the point of raising it so it wouldn't hit something?

 

[tashasdaddy]

Re: Watch this guy trash his U-joints!

raise the motor and do not try to go thru wide open.

 

[haulnazz15]

Re: Watch this guy trash his U-joints!

Also, don't raise the motor into the trailer position. The only safe speed in the trailer position is at idle, and even that is bad on the u-joints. I wouldn't go above idle when you are at the upper trim limit, much less the trailer position.

 

[QC]

Re: Watch this guy trash his U-joints!

Upper trim limit is designed to specifically be safe for full power . . . that's the point. Agree, idle only full tilt, but trim? That's how you get your best top speed if your boat and limit are set up right, annnnndddd . . . full down trim is also not straight, so in effect same as full up trim. I am not positive on the comparable angles, but think about it. What about turning?

 

[skargo]

Re: Watch this guy trash his U-joints!

Upper trim limit is designed to specifically be safe for full power . . . that's the point. Agree, idle only full tilt, but trim? That's how you get your best top speed if your boat and limit are set up right, annnnndddd . . . full down trim is also not straight, so in effect same as full up trim. I am not positive on the comparable angles, but think about it. What about turning?

Exactly what I was thinking.

 

[SeanT]

Re: Watch this guy trash his U-joints!

Good thread. I've learned here that you shouldn't rev the engine hard on the muffs, and so I've avoided it.

But a large percentage of the time I warmed up on the mufffs before heading to the ramp to launch, I had the leg all the way up at idle.

 

[JimKW]

Re: Watch this guy trash his U-joints!

When I start mine on the muffs before going out I always have it in trailer postition. I never rev it more than around 1500. Should I lower it from now on to start it on the muffs? I really had no idea.

 

[Gary H NC]

Re: Watch this guy trash his U-joints!

When I start mine on the muffs before going out I always have it in trailer postition. I never rev it more than around 1500. Should I lower it from now on to start it on the muffs? I really had no idea.

YES!