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Is throttle cable "stretch" possible?

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cbigma

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I have a single 2000 Yamaha 225 OX66 transom-mounted on a 25MVSC. The control is the OEM Yamaha 704 single lever. During the 2004 Season my WOT was at ~ 5400 rpm. During the 2005 Season my throttle travel maxed out at only ~4900. I’m sure the engine had more to go, but my control handle was at the travel limit (hitting the dash).
:(

When I quizzed the Yamaha Service Tech during my winterization visit, he explained that there are no throttle adjustments that can be made to bring me back up to higher RPMs and it’s a cable-travel issue. He claimed the cable is stretched and needs to be replaced.

I gotta believe there are some threaded-rod linkage adjustments that could be made to squeeze that extra 500 RPM back out (maybe just a single thread rotation?) without replacing the whole Teleflex cable.

But I really don’t want to just go in there and start messing with linkages and adjustments. Engine is otherwise in top shape (compression excellent etc.) and there is no other apparent reason that I lost the top 500 rpm

What's the verdict? Is throttle cable "stretch" a real possibility, or am I getting conned?
 

DaleH

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cbigma":1tdkcdl4 said:
What's the verdict? Is throttle cable "stretch" a real possibility, or am I getting conned?
Yes, cable stretch is real, but I usually have seen it in one of 2 cases - occuring either a week or two after "new" cables were installed or after a looooong number of years on the cables. I'm surprised, but not in a bad way, to hear this happening on your 2000 rig.

I could help you with this, but the adjustment is simple. But let me ask you ... have you noticed is idling lower? If not, what's probably happening, is then when you idle down, the idle throttle control is at it's stop (so it can't go lower) but the cable might still be moving. Sometimes making an adjustment on one end can affect the other end ... again, I could help you with this on site.

Can I ask ... have you ever decarb'd that OB?



ve seen it before,
 

Megabyte

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Andy over at Shipyard Island Marine posted photos once that showed how to adjust the throttle tensioner so that a Yamaha 704 control would hold throttle position... But I also seem to recall there was a tensioner there to take out cable slack too.

Does anyone else remember that post?
 

cbigma

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DaleH":3u7up5lx said:
Can I ask ... have you ever decarb'd that OB?
Yessir! After every season. Like brushing her teeth before I put her to bed for the winter. :lol:
 

cbigma

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DaleH":366ag51c said:
But let me ask you ... have you noticed is idling lower?
I -did- have the YamTech drop the idle RPM a tad at the end of the 2004 season. I felt like it was idling too high, because when I dropped her in and out of gear for docking it felt like a really "hard" shift. Not a "Bang" but an uncomfortable "thud". :shock:

He dropped the idle,,, and shifting during the 2005 season was much smoother,,, but I didn't know it was going to cost me 500 rpms on the upper range :(

So,,, they can't lower my idle without dropping the WOT max at the same time?
Is it like a finite cable length to travel over a range of RPMs and I have to choose where I start and that determines where I end?

If I had to choose I guess I would stick with the lower idle, save the wear and tear during shifting, and just live without the 40MPH+ top end. 8)
 

cbigma

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Megabyte":2n1qrk2y said:
Andy over at Shipyard Island Marine posted photos once that showed how to adjust the throttle tensioner so that a Yamaha 704 control would hold throttle position... But I also seem to recall there was a tensioner there to take out cable slack too.

Does anyone else remember that post?
I did a couple of searches on THT, and got nada...but I will ping Andy seperately and see what he knows about the 704 and slack adjustments...maybe he's got a "magic cable shrinker" or somethin...

Thanks Kevin.
 

TomS

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I know that thread.. I wanted to make the adjustment on my 704.. the pictures that Andy posted all pointed to thehulltruth.net, so I updated the links to point to thehulltruth.com.. anyways, here is the thread you are looking for:

http://www.thehulltruth.com/forums/thre ... 16#M766066


cbigma, when you are maxing out the throttle, is your engine stuttering at all, or still running strong?

You might want to check the TPS to see if its still in spec.

-- Tom
 

cbigma

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Awesome Job Tom! Not just total recall,,,,but -recovery- too! :p

Unfortunately I started the job just before I covered up in the fall, and you know when it gets to this part...about the seized screws?
Some of you saltwater guys may have a hard time getting these off from corrosion. Try tightening them first, then loosen. Work them back and forth since they snap easily
well,,, I can most assuredly attest to the fact that those screws will indeed snap. :shock:
So I drilled out the two that snapped, and will clear the drilled pegs with easy-outs in the spring.
Andy's post clearly shows the screw holes I am dealing with now and will make replacement a snap! (pun intended)
I see where Andy's post addresses "throttle friction" which I presume is the level of effort required to move the throttles along their arc.
But I can't see anything that refers to adjusting the actual limits of the throttle travel at WOT. Or pulling the "stretch" out.
Maybe I am missing something, and maybe all the adjustment for that variable is under the Engine cover, not the other end under the 704 Cover.
There was absolutely no stuttering or hesitation at WOT this year.
Plenty more there available, just couldn't get to it..... :cry:

Thanks again for the thread resurrection, I am going to print it out in color, as a "shop manual" for this spring. :D

John
 

Megabyte

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cbigma":z24aassf said:
I see where Andy's post addresses "throttle friction" which I presume is the level of effort required to move the throttles along their arc.
But I can't see anything that refers to adjusting the actual limits of the throttle travel at WOT. Or pulling the "stretch" out.
Thats probably my fault. I thought Andys posting did both.
I remembered the part about adjusting the friction, but couldn't recall if it also included taking the slack out.

Maybe you could send him an email on that topic...

As someone else mentioned... the adjustment could be in the area of the Throttle Position Sensor (TPS), though that isn't something I've ever dealt with.

Good luck!
 

cbigma

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Megabyte":k9pe348p said:
Maybe you could send him an email on that topic...
Even better, I sent him a link to this thread :D haven't seen him on the memberlist yet! Since OEM Parkers = Yamaha, I think he would want to be aware of ClassicParker.com.
 

SIM

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Hey guys!

Cool site....and anywhere there are Yamaha's and DY owners I want to be there! :lol:

Did your tech actually check and see where the engines throttle is actually at when the handle is at full throttle? I would determine that first. It very well may be at WOT and the engine is not running correctly.

Engine off.......Put the throttle handle at WOT and go back by the engine and remove the cable end from the throttle attachment. The manually with your hand advance the engines throttle mech and see if it has anymore travel. If it does not push anymore, then you have an engine running issue.

Andy
 

cbigma

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Wow! Now -That's- what I'm talking about.... :mrgreen:
It took Andy less than 10 minutes to Register at ClassicParker.com, and give me a clue to solving my problem!
And it would have been sooner, but he was on the phone walking someone through a manifold replacement job a the same time! :lol:
Where else but SIM could you -ever- get that kind of Yamaha-speak in a blink?
Thanks Andy.
 
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